New Circuits Page 227
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These are simple AVR programmers. I designed and built four different programmers for various envilonments: LPT controlled parallel programmer, LPT controlled ISP adapter, COM controlled ISP adapter and COM controlled generic SPI bridge. Additionaly, COM....
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The Lazy Adapter is composed of a 20 pin DIP socket, a 20 pin DIP header, and 6 pin ISP header, and a small phenolic circuit board to hold them all together. The green fiberglass PCB is a Dontronics DT104 SIMSTIC(This plug is in return for a favor.) I am....
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A straightforward circuit using a LM311 for the level detector and a CMOS analog gate to discharge the capacitor is shown. An important property of this type of counter is the ease with which the count can be changed; it is only necessary to change the....
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This circuit is intended for use in a small private telephone installation. The ringing tone sequence is 400 ms on, 200 ms off, 400 ms on, 2 ms off. In the accompanying diagram, N1 and N2 form an oscillator that operates at a frequency of 5 Hz, which gives....
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There are many 9V chaser circuits that seem to waste about 7V when driving LEDs that are only about 2V. This project is unique, because it uses only two inexpensive alkaline battery cells totaling 3V for power. Since most of the waste is eliminated, the....
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The high switching speed, low offset current and low offset voltage of the HA-4900 series make this window detector extreme..
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A simple battery-powered switching regulator provides 5 V outfrom a 9-V source with 80% efficiency and 50 mA output capability. When Q1 is on, its collector voltage rises, forcing current through the inductor. The output voltage rises, causing A1"s output....
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Up to eight players each have their own answer button to press, corresponding to the four Red Team and four Green Team LEDs on the master control board. As soon as the first contestant who thinks that he knows the answer presses the button, a loud tone....
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It can safely charge a 7-cell RC2000 pack in about 14 minutes, and an RC2400 or CP2400SCR pack in about 17 minutes. As a NiCd cell is being charged, two things happen which affect its temperature. Due to resistive losses within the cell, some of the charging....
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In the video system of Figs. A and R, a single coaxial cable carries power to the remote location, selects one of eight video channels, and returns the selected signal. The system can choose one of several remote surveillance-camera signals, for example,....
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The circuit use one simple, but good power supply, is enough its armor-clad by the remainder circuit, if it needs, with a aluminium, so that we avoid the noises. All the circuit can be placed in a small box, from which will only come out the RCA jack, the....
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This program uses an 8 bit DAC along with a 16F84 PIC microcontroller to generate a keyed sine wave. The 16F84 uses an RC clock which can be varied (with a suitable potentiometer) to allow a variable frequency control for the sine wave output. A key or keyer....
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Here`s a simple project that sends continuous or switch controller MIDI messages that correspond to the position of a potentiometer. Given a few parts and a cannibalized volume or wah-wah pedal, you can build this MIDI controller pedal and have the ultimate....
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Using inexpensive components, you can fit a simple probe circuit into a pencil-sized enclosure. When both LEDs are on, the probe indicates the presence of an ac voltage; either LED alone indicates the presence and polarity of a dc voltage. The diode-bridge....
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Having found an u664b prescaler chip (Telefunken) from an old tv-tuner , I decided to build a valid frequency counter using pic16f84 , the prescaler I use is able to divide by 64 every frequency from 30 to 1300 MHZ. The original project is from Peter....
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The simple and inexpensive circuit in Figure 1 monitors the liquid level in a container. The piezo crystal, carefully mounted at the bottom surface of the container, receives it activation from the 74HCT14 hex Schmitt trigger. The crystal generates stable....
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The basic clock circuit (top schematic below) is similar to the binary clock (on another page) and uses 7 ICs to produce the 20 digital bits for 12 hour time, plus AM and PM. A standard watch crystal oscillator (32,768) is used as the time base and is....
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With this circuit you will be able to monitor the quality of the mains. There are 4 distinct sections, each supervising a parameter pertinent to the quality of the supply line. The noise section consists of a 50Hz filter and a speaker where you will hear the....
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The probe described here was designed to be used over the range of several tens of Hz to a couple MHz with currents from a few tens of milliamps to about 10 amps peak-to-peak. Formulae are give which will allow you to create a design suitable for your own....
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The gEDA project has produced and continues working on a full GPL`d suite of Electronic Design Automation tools. These tools are used for electrical circuit design, schematic capture, simulation, prototyping, and production. Currently, the gEDA project....
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This launch controller can be used with low voltage battery igniters, which fire rocket engines in model rockets such as the Estes range. These circuits are electrical, only switches and contacts are involved. First the circuit for a single rocket...
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This circuit adapts a frequency counter to measure intervals. It was originally used as a shutter speed checker for a photo application. The watch ticks are clipped and shaped and formed into a square wave. This square wave is used to gate an accurately....
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This is a simple LED circuit that takes power from the USB port. I needed this USB light since long time ago but, finally; I was able to build it. The circuit schematic is so simple: Just one resistor and one White LED. I did use a 10,000mcd white LED. It....
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A 0-to-5 V input drives the negative input of LM392 comparator if reset (pin 12) if DC4060BE is pulled high then low, all out..
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This is an image Schematic. No Description available...
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This H-bridge variant was one of the first in which the reversing circuitry is built into the driver, rather than (as is more-commonly done) into the control circuitry upstream of the driver. This is a handy circuit, though, for 2-motor walkers -- as all....
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Using the CA3164A BiMOS control chip consumes less than 15 pA during standby, yet it can provide 100 mA of chopped current to the de-to-de converter during the energy-reservoir charging cycle. The CA3164A drives tbe primary of T1 with symmetrically chopped....
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You will find this identical circuit inside most 3 wire computer fans with speed monitoring output to the motherboard. Peel off the sticker from the fan hub in order to access a motor winding pin for connecting up the tacho circuit...
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Using a thermistor in the position shown makes a heat activated sensor. A change in temperature will alter the output of the opamp and energize the relay and light the LED. Swapping the position of the< thermistor and 47k resistor makes a cold or frost....
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This circuit has the CMOS IC doing double-duty performance. The first two inverters operate as a digital audio oscillator; the third operates as a low-gain linear audio amplifier. As the intensity of the light falling on photoresistor LDRl increases the....
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The circuit needs 15 volts and uses a precision op amp CA3193 BiMOS to amplify the signal generated more than 500 times. Three 22-megohm resistors provide large-scale output if the thermocouple opens.
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After the first cycle. the relay will normally be energized. When normally closed pushbutton 51 is activated, the SCR turns off, the relay is de-energized, and power is applied to the relaxation oscillator and the load. Mter a time delay varying from....
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This design was developed by request of a correspondent having made a sort of LED candle and needing to switch off the LED with a puff.
This simple, easy to build gadget can be useful as a prop for Halloween and Christmas season, shows and the like...
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In order to achieve a status between two levels of switching for two calls at the same time, you must first establish privacy on each call. Otherwise, you will end up with all four phones talking to each other, and that just won't do. So the Link 'P' is an....
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Adding two passive components to a standard photodiode amplifier reduces noise. Without the modification, the shunt capacitance of the photodiode reacting with the relatively large feedback resistor of the transimpedance (current-to-voltage) amplifier,....
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Ql and Q2 constitute a simple, high-speed FET input buffer.·Ql functions as a source follower, with the Q2 current-source load setting the drain-source channel current. The LT1010 buffer provides output drive capability for cables or whatever load is....
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Useful for A/B control, the IR receiver shown controls a relay from an infrared beam that has a pulsed tone-modulated signal. Ql is the photo receptor feeding op amp IC1, tone decoder IC2, and flip-flop IC3...
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When the sensor detects movement in a room it will take a burst of 10 photos with the digital camera. Each photo is taken at 0.5sec interval. After the 10 photos, the camera waits 3 seconds for further movement and if it is detected, the process is repeated....
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For those who are still with me, the preamp featured has optional tone and balance controls which may be omitted if desired (although I do not recommend this generally). The input switching may be extended if needed to accommodate more signal sources,....
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Using an NEC70083, this 1296-MHz amplifier delivers about 17-dB gain and around 1- to 1.5-dB noise. It is constructed..
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Simple frequency limit detectors providing a GO/NO-GO output for use with varying amplitude input signals may be conveniently implemented with the ICL8211/8212. In the application shown, the first ICL8212 is used as a zero-crossing detector. The output....
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The following circuit enables me to measure inductance of the inductor labeled LX which is the inductance to be measured. The o/p of the circuit is a TTL square wave whose frequency relates to the inductance being measured. The heart of the circuit is the....
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If you need a wide-range, resistor-programmable monostable multivibrator, you can program tbe circuit for pulse widths from 1 JlS to 10s-107:1 range. A high-to-low transition at tbe input causes IC1"s output to switch low, thereby turning off Q1 and Q2.....
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The circuit is based on IC1, which is a 555 timer IC in astable mode. It will power a 6 inch 4 Watt fluorescent tube off a 12 volt supply, consuming 300 mA. It may also be powered by a suitably rated universal AC/DC adapter. Advantages of the design are:....
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Detection of line-current flow and indicating the flow to an electrically remote point is required in line status monitoring at a variety of points in theJelephone system and auxiliary systems. The line should be minimally unbalanced or loaded by the....
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The reset switch on a computer is very important. If an operating instruction threatens to wreck the internal mana..
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The Colpitis sinusoidal oscillator provides stable output amplitude and frequency from 0°F to +150°F. In addition, output amplitude is large and harmonic distortion is low. Oscillation is sustained by feedback from the collector tank circuit to the....
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Sound detected by electret microphone MIC1 is fed to IC1"s input through resistor R2, and capacitors Cl and C2. Resistors R2 and R5 determine the overall stage gain, while C2 partially determines the amplifier"s frequency response. To ensure proper....
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This preamplifier was designed as a stand-alone portable unit, useful to control the signals generated by guitar pick-ups, particularly the contact "bug" types applied to acoustic instruments. Obviously it can be used with any type of instrument and pick-up.....
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The crystal oscillator, which uses two sections of IC1, a 4001 quad 2-input NOR gate, is a standard and reliable design. The oscillator"s 1.85-MHz, square-wave output feeds IC2, a 4017 divide-by-10 counter. The count enable and reset terminals, pins 13 and....
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The project was originally intended as a present for my brothers dorm room, but a bad capacitor and the lack of a proper oscilloscope caused delays. It has not made it off the breadboard, and it probably will not until his next semester. The circuit contains....
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This supply uses an SGS-Thomson UC3842 IC in an off-line flyback regulator, providing + 5 V at 4 A..
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One can transform an ordinary binary counter, such as a 7493, into an up/down counter with mode control by adding XOR gates 7486 to the counter"s outputs. The circuit counts up when the DN/UP line is low and down when the DN/UP line is high. To use the....
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RF is just way too cool not to use in your designs. But if you`re a newbie like me it is difficult to successfully build solid RF transmitters and receivers. When I started out I didn`t realize that the larger breadboard I was working off of was causing a....
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To model an LED in PSpice, use the diode model. You can set the IFK and ISR parameters in the diode model to zero; Figure 1 shows the resultant PSpice diode forward-current model and corresponding equations. As the equations in the figure show, you can....
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Using just four transistors and six resistors, this circuit provides switchable, constant-current drive for an LED and indicates both open- and short-circuit fault conditions (Figure 1). And there`s a bonus, too. Control signal VCONT switches the LED on and....
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This is a practical white LED head mount lamp (flashlight). Recently many white LED flashlights appear on the market. However, most flashlights require three cells because they are regurating output current with only series resister. The odd number of cells....
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Transistors Ql and Q2, together with resistors Rl through R7, make up the input balancing stage, which senses the resistance between points X and Y. The input stage is essentially a bridge, consisting of Rl, R2, R6, R7, and the resistance between points X....
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The 2 pushbuttons = S1: Start/Pause. S2: Stop/Reset. If you want to play your message, put S3 at Play. Then push S1 to start playing and again to pause. If you want to delete your message press S2 twice. If you want to record a message put S3 at Rec. Then....
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When transistor Q1 is switched off, the circuit behaves as a voltage follower. By applying a positive vol..
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Here is the schematic, PC board pattern, and parts placement for a low powered FM transmitter. The range of the transmitter when running at 9V is about 300 feet. Running it from 12V increases the range to about 400 feet. This transmitter should not be used....
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Electric is a sophisticated electrical CAD system that can handle many forms of circuit design, including:
* Custom IC layout (ASICs)
* Schematic drawing
* Hardware description language specifications..
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I made this project as a test to improve a technic to read analog values without analog-to-digital converter. (ADC) I ended with this "sound meter". It may not work perfectly, it needs some improvement but works anyway. It have the feature of....
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This inverter can deliver .high-voltage ac or de, with a rectifier and filter, up to several hundred volts. The secondary and primary of T1-a 12.6 to 440 V power transformer, respectively-are reversed; e.g., the primary becomes the secondary and the....
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PT2350 is a tone control subwoofer cross-over low pass filter chip utilizing CMOS Technology. It features a tone control range of + 10dB (50Hz, 4 KHz) and subwoofer low pass filter of the second order Sallen Key Design. The roll-off point can be adjusted by....
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This circuit will double low-level signals with low distortion. The value of C should be chosen for low reactance at the operating frequency. Signal level at the carrier input must be less than 25 mV peak to maintain operation in the linear region of the....
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Motorola MWA 110, 120, or 130 are wideband amplifier ICs. This wideband preamp circuit can be used in many applications. Keep the leads short when constructing the circuitry. PC board layout (shading represents copper) and parts layout. X is the feedthrough....
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The circuit above illustrates using the IR receiver module along
with a PIC12F629 microcontroller to decode 5 individual IR remote
control keys so the circuit will only toggle one of the 4 outputs
when a particular key is pressed. The 5th key is....
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An external power supply that gives a voltage higher than the highest expected rating of the zener diodes to be tested is required. Potentiometer RVl is adjusted until the meter reading stabilizes..
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A laptop computer supply that has 9-V output, crowbar overvoltage protection, and operates i`rom a 12-V supply is shown above. The supply voltage should be at least 3.6 V above the expected output voltage. Ql should be heatsinked appropriately. R5 should....
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L1 is a loop of 10 to 20 turns of insulated wire with a diameter anywhere between 4" to 4'. Oscillator frequency (7 to 30 MHz) shifts substantially when a person comes near or into the loop. This oscillator together with a resonant detector might make a very....
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A complete digital dimming system includes the dimming
ballasts and a digital control unit for converting information
from an Ethernet connection to the communication protocol
required by the micro-controller in each ballast (Figure 1).
Applications for....
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The JFET-bipolar cascode circuit will provide full video output for the CRT cathode drive. Gain is about 90. The cascode configura-tioneliminates Miller capacitance problems with the 2N4091 JFET, thus allowing direct drive from the video detector..
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The FM Snooper is an FM transmitter that radiates a continuous wave whose frequency is altered according to the sound waves striking the microphone. An ordinary FM broadcast receiver detects the transmitter"s output carrier. When 9-V battery, B1, is....
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Transistor Ql and resistors Rl, R2, and R3 form a constant current source and the charge current might be adjusted..
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This voltmeter exploits a number of tbe CA3160 BiMOS op amp"s useful characteristics. The available voltage ranges from 10 mV to 300 V. Powered by a single 8.4-V mercury battery, this circuit, with zero input, consumes approximately 500 p,A. ..
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The A/B Switch circuit consists of three ICs and a handful of resistors. Two gates from a 4011 quad 2-input N..
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The circuit uses a CA3060 triple OTA (two units serve as switched current generators controlled by a third amplifier). A CA3160 BiMOS op amp serves as a voltage follower to buffer the 0.0022 µ¥ integrating capacitor. The circuit has an adjustment range of....
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The various signal frequencies are obtained for an incoming carrier centered at 49.86 MHz. The receiver employs double conversion, with i-fs at 10.7 MHz and 455kHz. Ceramic filters are used in both i-fs for selectivity and reduced"coil count. A quadrature....
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The circuit works from dc to 50 MHz and will deliver pulses as short as 10 ns. It is driven by a TTL signal through a 740S00 quad Schottky NAND gate, ICA through ICD. Transistor Ql, wired as a common-emitter amplifier, drives transistor Q2, a simple emitter....
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This Charger Can't be used as a Power Supply, Without having a battery in place. The Battery MUST be Connected to get power out. Note: This Charger Features a Reverse polarity Indicator. Instructions: Before plugging this charger into the 110 volt line (or....
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Continuity tester to check continuity in the circuit (Insakittochekka) is. The continuity check over the circuit board wiring that can be checked at a lower voltage semiconductors do not conduct contained in the circuit, you can just check the wiring short....
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This is my long history the device that controls my home`s night light, air-conditioner,etc. The device is a Miniature Real-time Controller. The circuit uses only three chips, a 89C2051, DS275(or MAX232), and 74LS07 open collector driver. The scheduler for....
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The Project Long Range Remote Control can be used to remotely control a number of Electrical or Electronic Gadgets connected to it. Unlike Infra Red remote control, this Project employs FM transmission and Reception, and hence it can be used for....
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Integrated-circuit U1-an LF351 or 741 op amp-is used as a comparator to control the light. Resistors R2 and R3 provide a reference voltage of about 2.5 volts at pin 3 of U1. When daylight falls on light-dependent resistor LDR1, its resistance is low: about....
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Shown here arc several possible interface circuits that can be used with the remote-control transmitter. The one in A illustrates a typical FM stereo MUX decoder with a load connected directly to the open-collector output of a TA7343 PLL. The circuit in....
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The crystal is placed between the collector of the output stage and the base of the input stage. The frequency of oscillation can be set to a precise value with trimmer capacitor CI. The range of operation for this circuit is 500 kHz to 10 MHz..
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The digital delay presented here is expected to be sufficient for most applications, and although the delay is fixed at 20ms, this is the most usable delay period. This is the equivalent of being about 7 metres away from the rear speakers, and they will have....
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The circuit has a typical voltage gain of 84 dB and a typical AGC range of 80 dB. It gives very small changes in bandpass shape, usually less than 1 dB tilt for 60 dB compression. There are no shielded sections. The detector uses a single tuned circuit (L3....
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This circuit uses a 555 timer in the bistable mode. Touching T2 causes the output to go high; D2 conducts and D1 extinguishes. Touching T1 causes the output to go low; D1 conducts and D2 is cut off. The output from pin 3 can also be used to operate other....
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ICl-c functions as a noninverting comparator, and ICl-a operates as an inverting comparator. Potentiometer Rl and fixed resistors R2 and R3 form a divider chain that delivers slightly different voltages to the two comparators. These voltages define the....
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This stun gun is powered by a 9V battery. The transformer steps up the voltage to about 1800V (but with very low current). A 555 timer IC is used to generate a high-frequency output. A 1 MEG variable resistor can also be used at the output to drop the....
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The circuit in Figure 1 performs active voltage-to-current conversion or acts as a variable-gain current mirror with high precision and bandwidth. A typical application is testing high-speed ICs or other devices that have inputs designed to be driven from....
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This is a simple low-level noise maker that`s ideally suited to certain alarm applications. When the sounder is located in another part of the building, the sound level is loud enough to be heard, but is not loud enough to warn off an intruder. A single....
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The signal starts at a low frequency, rises for about 1.15 seconds to a high frequency, ceases for about 0.35 seconds, then starts rising again from a low frequency, and so on ad infinitum.
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Seven-V narrow pulses from 2 Hz to 50 kHz are produced by this circuit. CI through C4 provide frequency ranges i..
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Audio light modulations add to the enjoyment of music during functions organised at home or outdoors. Presented here is one such simple circuit in which light is modulated using a small fraction of the audio output from the speaker terminals of the audio....
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The control voltage is fed into the first half of a 1458 op-amp, this stage inverts the signal and sets the offset and gain for the right channel gain control circuit. This signal is then fed into the second half of the 1458 op-amp which inverts the voltage....
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The circuit ICL7134B base is a bipolar input AID converter broadband, using two AM25L03s to form a successive approximation register 14-bit. The comparator is a circuit with two stage amplifier HA2605 front, used to reduce the settling time problems in the....
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A lot of friends ask me a circuit AUDIO MIXER, for various uses. I will begin with a circuit which you can it manufacture, as you want. This you can place in the MODULES of inputs any circuit you want, depending on the use that you intend the MIXER, the same....
These are simple AVR programmers. I designed and built four different programmers for various envilonments: LPT controlled parallel programmer, LPT controlled ISP adapter, COM controlled ISP adapter and COM controlled generic SPI bridge. Additionaly, COM....
The Lazy Adapter is composed of a 20 pin DIP socket, a 20 pin DIP header, and 6 pin ISP header, and a small phenolic circuit board to hold them all together. The green fiberglass PCB is a Dontronics DT104 SIMSTIC(This plug is in return for a favor.) I am....
A straightforward circuit using a LM311 for the level detector and a CMOS analog gate to discharge the capacitor is shown. An important property of this type of counter is the ease with which the count can be changed; it is only necessary to change the....
This circuit is intended for use in a small private telephone installation. The ringing tone sequence is 400 ms on, 200 ms off, 400 ms on, 2 ms off. In the accompanying diagram, N1 and N2 form an oscillator that operates at a frequency of 5 Hz, which gives....
There are many 9V chaser circuits that seem to waste about 7V when driving LEDs that are only about 2V. This project is unique, because it uses only two inexpensive alkaline battery cells totaling 3V for power. Since most of the waste is eliminated, the....
The high switching speed, low offset current and low offset voltage of the HA-4900 series make this window detector extreme..
A simple battery-powered switching regulator provides 5 V outfrom a 9-V source with 80% efficiency and 50 mA output capability. When Q1 is on, its collector voltage rises, forcing current through the inductor. The output voltage rises, causing A1"s output....
Up to eight players each have their own answer button to press, corresponding to the four Red Team and four Green Team LEDs on the master control board. As soon as the first contestant who thinks that he knows the answer presses the button, a loud tone....
It can safely charge a 7-cell RC2000 pack in about 14 minutes, and an RC2400 or CP2400SCR pack in about 17 minutes. As a NiCd cell is being charged, two things happen which affect its temperature. Due to resistive losses within the cell, some of the charging....
In the video system of Figs. A and R, a single coaxial cable carries power to the remote location, selects one of eight video channels, and returns the selected signal. The system can choose one of several remote surveillance-camera signals, for example,....
The circuit use one simple, but good power supply, is enough its armor-clad by the remainder circuit, if it needs, with a aluminium, so that we avoid the noises. All the circuit can be placed in a small box, from which will only come out the RCA jack, the....
This program uses an 8 bit DAC along with a 16F84 PIC microcontroller to generate a keyed sine wave. The 16F84 uses an RC clock which can be varied (with a suitable potentiometer) to allow a variable frequency control for the sine wave output. A key or keyer....
Here`s a simple project that sends continuous or switch controller MIDI messages that correspond to the position of a potentiometer. Given a few parts and a cannibalized volume or wah-wah pedal, you can build this MIDI controller pedal and have the ultimate....
Using inexpensive components, you can fit a simple probe circuit into a pencil-sized enclosure. When both LEDs are on, the probe indicates the presence of an ac voltage; either LED alone indicates the presence and polarity of a dc voltage. The diode-bridge....
Having found an u664b prescaler chip (Telefunken) from an old tv-tuner , I decided to build a valid frequency counter using pic16f84 , the prescaler I use is able to divide by 64 every frequency from 30 to 1300 MHZ. The original project is from Peter....
The simple and inexpensive circuit in Figure 1 monitors the liquid level in a container. The piezo crystal, carefully mounted at the bottom surface of the container, receives it activation from the 74HCT14 hex Schmitt trigger. The crystal generates stable....
The basic clock circuit (top schematic below) is similar to the binary clock (on another page) and uses 7 ICs to produce the 20 digital bits for 12 hour time, plus AM and PM. A standard watch crystal oscillator (32,768) is used as the time base and is....
With this circuit you will be able to monitor the quality of the mains. There are 4 distinct sections, each supervising a parameter pertinent to the quality of the supply line. The noise section consists of a 50Hz filter and a speaker where you will hear the....
The probe described here was designed to be used over the range of several tens of Hz to a couple MHz with currents from a few tens of milliamps to about 10 amps peak-to-peak. Formulae are give which will allow you to create a design suitable for your own....
This launch controller can be used with low voltage battery igniters, which fire rocket engines in model rockets such as the Estes range. These circuits are electrical, only switches and contacts are involved. First the circuit for a single rocket...
This circuit adapts a frequency counter to measure intervals. It was originally used as a shutter speed checker for a photo application. The watch ticks are clipped and shaped and formed into a square wave. This square wave is used to gate an accurately....
This is a simple LED circuit that takes power from the USB port. I needed this USB light since long time ago but, finally; I was able to build it. The circuit schematic is so simple: Just one resistor and one White LED. I did use a 10,000mcd white LED. It....
A 0-to-5 V input drives the negative input of LM392 comparator if reset (pin 12) if DC4060BE is pulled high then low, all out..
This H-bridge variant was one of the first in which the reversing circuitry is built into the driver, rather than (as is more-commonly done) into the control circuitry upstream of the driver. This is a handy circuit, though, for 2-motor walkers -- as all....
Using the CA3164A BiMOS control chip consumes less than 15 pA during standby, yet it can provide 100 mA of chopped current to the de-to-de converter during the energy-reservoir charging cycle. The CA3164A drives tbe primary of T1 with symmetrically chopped....
You will find this identical circuit inside most 3 wire computer fans with speed monitoring output to the motherboard. Peel off the sticker from the fan hub in order to access a motor winding pin for connecting up the tacho circuit...
Using a thermistor in the position shown makes a heat activated sensor. A change in temperature will alter the output of the opamp and energize the relay and light the LED. Swapping the position of the< thermistor and 47k resistor makes a cold or frost....
This circuit has the CMOS IC doing double-duty performance. The first two inverters operate as a digital audio oscillator; the third operates as a low-gain linear audio amplifier. As the intensity of the light falling on photoresistor LDRl increases the....
The circuit needs 15 volts and uses a precision op amp CA3193 BiMOS to amplify the signal generated more than 500 times. Three 22-megohm resistors provide large-scale output if the thermocouple opens. ..
After the first cycle. the relay will normally be energized. When normally closed pushbutton 51 is activated, the SCR turns off, the relay is de-energized, and power is applied to the relaxation oscillator and the load. Mter a time delay varying from....
This design was developed by request of a correspondent having made a sort of LED candle and needing to switch off the LED with a puff. This simple, easy to build gadget can be useful as a prop for Halloween and Christmas season, shows and the like...
In order to achieve a status between two levels of switching for two calls at the same time, you must first establish privacy on each call. Otherwise, you will end up with all four phones talking to each other, and that just won't do. So the Link 'P' is an....
Adding two passive components to a standard photodiode amplifier reduces noise. Without the modification, the shunt capacitance of the photodiode reacting with the relatively large feedback resistor of the transimpedance (current-to-voltage) amplifier,....
Ql and Q2 constitute a simple, high-speed FET input buffer.·Ql functions as a source follower, with the Q2 current-source load setting the drain-source channel current. The LT1010 buffer provides output drive capability for cables or whatever load is....
Useful for A/B control, the IR receiver shown controls a relay from an infrared beam that has a pulsed tone-modulated signal. Ql is the photo receptor feeding op amp IC1, tone decoder IC2, and flip-flop IC3...
When the sensor detects movement in a room it will take a burst of 10 photos with the digital camera. Each photo is taken at 0.5sec interval. After the 10 photos, the camera waits 3 seconds for further movement and if it is detected, the process is repeated....
For those who are still with me, the preamp featured has optional tone and balance controls which may be omitted if desired (although I do not recommend this generally). The input switching may be extended if needed to accommodate more signal sources,....
Using an NEC70083, this 1296-MHz amplifier delivers about 17-dB gain and around 1- to 1.5-dB noise. It is constructed..
Simple frequency limit detectors providing a GO/NO-GO output for use with varying amplitude input signals may be conveniently implemented with the ICL8211/8212. In the application shown, the first ICL8212 is used as a zero-crossing detector. The output....
The following circuit enables me to measure inductance of the inductor labeled LX which is the inductance to be measured. The o/p of the circuit is a TTL square wave whose frequency relates to the inductance being measured. The heart of the circuit is the....
If you need a wide-range, resistor-programmable monostable multivibrator, you can program tbe circuit for pulse widths from 1 JlS to 10s-107:1 range. A high-to-low transition at tbe input causes IC1"s output to switch low, thereby turning off Q1 and Q2.....
The circuit is based on IC1, which is a 555 timer IC in astable mode. It will power a 6 inch 4 Watt fluorescent tube off a 12 volt supply, consuming 300 mA. It may also be powered by a suitably rated universal AC/DC adapter. Advantages of the design are:....
Detection of line-current flow and indicating the flow to an electrically remote point is required in line status monitoring at a variety of points in theJelephone system and auxiliary systems. The line should be minimally unbalanced or loaded by the....
The reset switch on a computer is very important. If an operating instruction threatens to wreck the internal mana..
The Colpitis sinusoidal oscillator provides stable output amplitude and frequency from 0°F to +150°F. In addition, output amplitude is large and harmonic distortion is low. Oscillation is sustained by feedback from the collector tank circuit to the....
Sound detected by electret microphone MIC1 is fed to IC1"s input through resistor R2, and capacitors Cl and C2. Resistors R2 and R5 determine the overall stage gain, while C2 partially determines the amplifier"s frequency response. To ensure proper....
This preamplifier was designed as a stand-alone portable unit, useful to control the signals generated by guitar pick-ups, particularly the contact "bug" types applied to acoustic instruments. Obviously it can be used with any type of instrument and pick-up.....
The crystal oscillator, which uses two sections of IC1, a 4001 quad 2-input NOR gate, is a standard and reliable design. The oscillator"s 1.85-MHz, square-wave output feeds IC2, a 4017 divide-by-10 counter. The count enable and reset terminals, pins 13 and....
The project was originally intended as a present for my brothers dorm room, but a bad capacitor and the lack of a proper oscilloscope caused delays. It has not made it off the breadboard, and it probably will not until his next semester. The circuit contains....
This supply uses an SGS-Thomson UC3842 IC in an off-line flyback regulator, providing + 5 V at 4 A..
One can transform an ordinary binary counter, such as a 7493, into an up/down counter with mode control by adding XOR gates 7486 to the counter"s outputs. The circuit counts up when the DN/UP line is low and down when the DN/UP line is high. To use the....
This is a practical white LED head mount lamp (flashlight). Recently many white LED flashlights appear on the market. However, most flashlights require three cells because they are regurating output current with only series resister. The odd number of cells....
Transistors Ql and Q2, together with resistors Rl through R7, make up the input balancing stage, which senses the resistance between points X and Y. The input stage is essentially a bridge, consisting of Rl, R2, R6, R7, and the resistance between points X....
The 2 pushbuttons = S1: Start/Pause. S2: Stop/Reset. If you want to play your message, put S3 at Play. Then push S1 to start playing and again to pause. If you want to delete your message press S2 twice. If you want to record a message put S3 at Rec. Then....
When transistor Q1 is switched off, the circuit behaves as a voltage follower. By applying a positive vol..
Here is the schematic, PC board pattern, and parts placement for a low powered FM transmitter. The range of the transmitter when running at 9V is about 300 feet. Running it from 12V increases the range to about 400 feet. This transmitter should not be used....
I made this project as a test to improve a technic to read analog values without analog-to-digital converter. (ADC) I ended with this "sound meter". It may not work perfectly, it needs some improvement but works anyway. It have the feature of....
This inverter can deliver .high-voltage ac or de, with a rectifier and filter, up to several hundred volts. The secondary and primary of T1-a 12.6 to 440 V power transformer, respectively-are reversed; e.g., the primary becomes the secondary and the....
PT2350 is a tone control subwoofer cross-over low pass filter chip utilizing CMOS Technology. It features a tone control range of + 10dB (50Hz, 4 KHz) and subwoofer low pass filter of the second order Sallen Key Design. The roll-off point can be adjusted by....
This circuit will double low-level signals with low distortion. The value of C should be chosen for low reactance at the operating frequency. Signal level at the carrier input must be less than 25 mV peak to maintain operation in the linear region of the....
Motorola MWA 110, 120, or 130 are wideband amplifier ICs. This wideband preamp circuit can be used in many applications. Keep the leads short when constructing the circuitry. PC board layout (shading represents copper) and parts layout. X is the feedthrough....
The circuit above illustrates using the IR receiver module along with a PIC12F629 microcontroller to decode 5 individual IR remote control keys so the circuit will only toggle one of the 4 outputs when a particular key is pressed. The 5th key is....
An external power supply that gives a voltage higher than the highest expected rating of the zener diodes to be tested is required. Potentiometer RVl is adjusted until the meter reading stabilizes..
A laptop computer supply that has 9-V output, crowbar overvoltage protection, and operates i`rom a 12-V supply is shown above. The supply voltage should be at least 3.6 V above the expected output voltage. Ql should be heatsinked appropriately. R5 should....
L1 is a loop of 10 to 20 turns of insulated wire with a diameter anywhere between 4" to 4'. Oscillator frequency (7 to 30 MHz) shifts substantially when a person comes near or into the loop. This oscillator together with a resonant detector might make a very....
The JFET-bipolar cascode circuit will provide full video output for the CRT cathode drive. Gain is about 90. The cascode configura-tioneliminates Miller capacitance problems with the 2N4091 JFET, thus allowing direct drive from the video detector..
The FM Snooper is an FM transmitter that radiates a continuous wave whose frequency is altered according to the sound waves striking the microphone. An ordinary FM broadcast receiver detects the transmitter"s output carrier. When 9-V battery, B1, is....
Transistor Ql and resistors Rl, R2, and R3 form a constant current source and the charge current might be adjusted..
This voltmeter exploits a number of tbe CA3160 BiMOS op amp"s useful characteristics. The available voltage ranges from 10 mV to 300 V. Powered by a single 8.4-V mercury battery, this circuit, with zero input, consumes approximately 500 p,A. ..
The A/B Switch circuit consists of three ICs and a handful of resistors. Two gates from a 4011 quad 2-input N..
The circuit uses a CA3060 triple OTA (two units serve as switched current generators controlled by a third amplifier). A CA3160 BiMOS op amp serves as a voltage follower to buffer the 0.0022 µ¥ integrating capacitor. The circuit has an adjustment range of....
The various signal frequencies are obtained for an incoming carrier centered at 49.86 MHz. The receiver employs double conversion, with i-fs at 10.7 MHz and 455kHz. Ceramic filters are used in both i-fs for selectivity and reduced"coil count. A quadrature....
The circuit works from dc to 50 MHz and will deliver pulses as short as 10 ns. It is driven by a TTL signal through a 740S00 quad Schottky NAND gate, ICA through ICD. Transistor Ql, wired as a common-emitter amplifier, drives transistor Q2, a simple emitter....
This Charger Can't be used as a Power Supply, Without having a battery in place. The Battery MUST be Connected to get power out. Note: This Charger Features a Reverse polarity Indicator. Instructions: Before plugging this charger into the 110 volt line (or....
Continuity tester to check continuity in the circuit (Insakittochekka) is. The continuity check over the circuit board wiring that can be checked at a lower voltage semiconductors do not conduct contained in the circuit, you can just check the wiring short....
This is my long history the device that controls my home`s night light, air-conditioner,etc. The device is a Miniature Real-time Controller. The circuit uses only three chips, a 89C2051, DS275(or MAX232), and 74LS07 open collector driver. The scheduler for....
The Project Long Range Remote Control can be used to remotely control a number of Electrical or Electronic Gadgets connected to it. Unlike Infra Red remote control, this Project employs FM transmission and Reception, and hence it can be used for....
Integrated-circuit U1-an LF351 or 741 op amp-is used as a comparator to control the light. Resistors R2 and R3 provide a reference voltage of about 2.5 volts at pin 3 of U1. When daylight falls on light-dependent resistor LDR1, its resistance is low: about....
Shown here arc several possible interface circuits that can be used with the remote-control transmitter. The one in A illustrates a typical FM stereo MUX decoder with a load connected directly to the open-collector output of a TA7343 PLL. The circuit in....
The crystal is placed between the collector of the output stage and the base of the input stage. The frequency of oscillation can be set to a precise value with trimmer capacitor CI. The range of operation for this circuit is 500 kHz to 10 MHz..
The digital delay presented here is expected to be sufficient for most applications, and although the delay is fixed at 20ms, this is the most usable delay period. This is the equivalent of being about 7 metres away from the rear speakers, and they will have....
The circuit has a typical voltage gain of 84 dB and a typical AGC range of 80 dB. It gives very small changes in bandpass shape, usually less than 1 dB tilt for 60 dB compression. There are no shielded sections. The detector uses a single tuned circuit (L3....
This circuit uses a 555 timer in the bistable mode. Touching T2 causes the output to go high; D2 conducts and D1 extinguishes. Touching T1 causes the output to go low; D1 conducts and D2 is cut off. The output from pin 3 can also be used to operate other....
ICl-c functions as a noninverting comparator, and ICl-a operates as an inverting comparator. Potentiometer Rl and fixed resistors R2 and R3 form a divider chain that delivers slightly different voltages to the two comparators. These voltages define the....
This stun gun is powered by a 9V battery. The transformer steps up the voltage to about 1800V (but with very low current). A 555 timer IC is used to generate a high-frequency output. A 1 MEG variable resistor can also be used at the output to drop the....
This is a simple low-level noise maker that`s ideally suited to certain alarm applications. When the sounder is located in another part of the building, the sound level is loud enough to be heard, but is not loud enough to warn off an intruder. A single....
The signal starts at a low frequency, rises for about 1.15 seconds to a high frequency, ceases for about 0.35 seconds, then starts rising again from a low frequency, and so on ad infinitum. ..
Seven-V narrow pulses from 2 Hz to 50 kHz are produced by this circuit. CI through C4 provide frequency ranges i..
Audio light modulations add to the enjoyment of music during functions organised at home or outdoors. Presented here is one such simple circuit in which light is modulated using a small fraction of the audio output from the speaker terminals of the audio....
The control voltage is fed into the first half of a 1458 op-amp, this stage inverts the signal and sets the offset and gain for the right channel gain control circuit. This signal is then fed into the second half of the 1458 op-amp which inverts the voltage....
The circuit ICL7134B base is a bipolar input AID converter broadband, using two AM25L03s to form a successive approximation register 14-bit. The comparator is a circuit with two stage amplifier HA2605 front, used to reduce the settling time problems in the....
A lot of friends ask me a circuit AUDIO MIXER, for various uses. I will begin with a circuit which you can it manufacture, as you want. This you can place in the MODULES of inputs any circuit you want, depending on the use that you intend the MIXER, the same....
