New Circuits Page 234
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This power supply is dedicated for use with rf equipments like, linear amplifiers, transmitters, receivers, and in every application that clean an-noisy signal is required. The circuit is very simple and you can drive it with a 220V/18V/3A transformer at the....
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Stick the metal probes into a freshly watered plant and adjust R5 for a mid-scale meter deflection. The meter will monitor the soil wetness and the meter will indicate whether it is to moist or to dry. This circuit uses a dual power supply which could be....
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The first circuit energizes the relay when the light rises above the preset level. The second circuit energizes the relay when the light falls below the preset level. The two circuits are practically identical. The only difference between them is the....
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The circuit connects to the speaker outputs of your stereo or to the back of your speaker. The music passes through the transformer and the volume level is adjusted by the 5k ohm pot. Each light bulb is turn on by a different frequency of sound based on the....
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The receiver chip uses a Panasonic 4602 38KHz receiver and that's it for external components. It has the serial input (GP3) , two RC hobby servo outputs (GP0/GP1) and three digital outputs (GP2,4,5). Here is the code for the receiver chip. It is a bit of a....
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Some applications require a circuit to indicate that a battery`s voltage has fallen below a certain value. However, if you don`t frequently check the indicator, the low-battery indicator itself can easily discharge the battery. The circuit in Figure 1....
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Class D audio amplifiers provide a dual benefit for battery-powered portable devices (Figure). They enhance battery life, and they produce much less power dissipation than do their linear cousins. Those features make Class D amplifiers ideal candidates for....
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This circuit is about as good as it gets for generating morse code tones. It may be used as a code practice oscillator, a tone generator for a keyer, a sidetone oscillator for a CW transmitter or an audio Modulated CW (MCW) generator for an FM transmitter or....
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The IR remote control for the system is also based on
a PIC10F200. It uses the wake-up on change function
of the I/O to wake it whenever a button is pressed. It
then generates one of two different modulated outputs,
depending on which button was pressed.....
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Opening SA, changes the indicator lamp from flashing to steady-lit condition. The 6-V incandescent lamp on the collector of Q2 requires about 0.3 A. A 1-KO load resistor limits Ql"s collector current to about 6 mA. ..
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High Quality unit with LM833 or NE5532 Low noise Dual Op-amp.
No need for a preamplifier. # Can be directly connected to CD players, tuners and tape recorders.
# Tested with several headphone models of different impedance: 32, 100, 245, 300, 600 & 2000....
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This circuit is designed to work at UHF frequencies in the range 450-800MHz. It has a gain of around 10dB and is suitable for boosting weak TV signals. The circuit is shown below...
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A Touch On/Off Switch is desired, this circuit fills the bill. Two sensitive gate SCRs are interconnected, so that when one of the devices is turned on, the other (if on) is forced off. That toggling effect gives an on/off circuit condition for each of the....
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A Variable DC Power Supply is one of the most useful tools on the electronics hobbyist`s workbench. This circuit is not an absolute novelty, but it is simple, reliable, "rugged" and short-proof, featuring variable voltage up to 24V and variable current....
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Here's another daft yet interesting PIC12F675 idea I came up with. When I wanted to show someone how logic gates worked I could only find a NAND gate which wasn't very handy for demonstrating AND's OR's, NOR's and ExOR's. I also wanted to have a play with....
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Since the speed of the I2C bus can be rather high, it is recommended to use a fast optocoupler. However, this circuit will not work on speeds higher then 10KHz. A 6N139 will do the job in all cases. The two PNP and the two NPN transistors can be any standard....
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This circuit uses LEDs to display the beat frequency of two-tone oscillators. Only one LED is on at a time, and the apparent rotation of the dot is an exact indication of the best frequency..
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There is enough of poorly constructed RS232 alike TTL level interfaces (+5volt) , this one generates it`s own +/- 10..11volts as RS232 specs. require , and is able to use very long cables like RS232 can , and protects computer as well , nice in funny....
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In the absence of radiation, no current is drawn. At normal background radiation levels the power consumption is extremely low. The instrument may be left on for several months without changing batteries. In this way the detector is always ready to indicate....
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This circuit uses the versatile MAX038 function generator. Although in this circuit some of the advanced characteristics of this IC are disabled, you can generate Sine, Triangle, Square waves (adjusting A0 and A1 pins see datasheet on www.maxim-ic.com if you....
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You can connect seven-segment LCDs using only a two-wire interface (Figure 1). The two-wire interface may be at the field-effect, direct-drive LCD or at a serial interface (such as I2C) that uses an eight-pin microcontroller. The design in Figure 1 uses an....
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The heart of the lock is the 40022 octal counter. When first powered C2 is charged via R5 so the reset input of the counter is kept high. That causes output Q to go high while all the other outputs are low. With the switches wired as shown, when S4 is....
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PSU Designer II is designed to help you with the design of simple linear (unregulated) mains power supplies, as often found in tube amplifiers...
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The voltage-to-current (V/I) converter in Figure 1 uses three common op amps, two medium-power transistors, and only a few passive components. The first op amp (IC1) inverts the sum of voltages VIN and VOUT to V1=-(VIN+VOUT). The second op amp (IC2) and....
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Originally I intended to have 32 faders. Once I tried fitting them on a veroboard, 32 seemed rather excessive so I have reduced to sixteen. This still allows generation of accurate eigth harmonic which compares well with the Hammond's ninth harmonic. A....
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This Circuit is based on the LM3876. A 11-pin plastic package IC with high performance audio power amplifier, an output mute function which can be used to eliminate switch-on and switch-off "thumps" to the loudspeaker load. It is capable of delivering 40W....
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This is an image Schematic. No Description available...
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The design incorporates 30-0, 1/4;.. microstrip lines on the input and output. C3, C4, C7, and C8, along with Ll, form a pi network that matches the low-input impedance of the device to 50 0. C5, C6, C9, ClO, and 30-0 transmission line L2 form an output pi....
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This circuit may be used where a high current is required with a low ripple voltage (such as in a high powered class AB amplifier when high quality reproduction is necessary), Ql, Q2, and R2 may be regarded as a power darlington transistor. ZDl and Rl....
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This software functions as a long period astable mutivibrator. The mark and space period can be set from 1 second up to a maximum 65535 seconds (18h12m15s). Using the internal 4Mhz RC oscillator delays with an accuracy of 99% or better can be achieved....
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This article is about a software controlled, parallel port-interfacing 8-channel Pulse-Width-Modulated fan controller. I'll admit that the electronic part of it isn't very advanced, but hopefully the idea of "interfacing" might be interesting.
My old....
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This 3 channel 15 LED spectrum analyzer is the perfect addition to any audio amp project. It produces fantastic displays on three LED bars that can be individually adjusted for any particular frequency range. The circuit will take line level output from most....
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The circuit of Figure 1 includes a PIN photodiode that detects individual photons of gamma radiation. The reverse bias on the photodiode sometimes creates a depletion region. When such a photon strikes this depletion region, a small amount of charge....
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You're simulating a circuit, it requires several digital gates, but you don't have a mixed-mode simulator. What to do? One solution involves creating simplified versions of the logic functions. To do this, we look to the NMOS transistor implementation of....
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The original design used a VCXO (voltage-controlled crystal oscillator) for this function, but this revised design implements an all-digital method that provided additional functions, using a midlevel CPLD from Altera (www.altera.com)...
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The circuit arrangement consists of a photo-amplifier which feeds a voltage derived from varying light levels in an enlarger to a pair of peak detectors. One follows the peak positive voltage and the other the peak negative voltage. The capacitors used for....
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Just the solution for AVR applications in which I/O is tight, such as the ATtiny12. This should work well on other kids of controllers that have independently controlled I/O direction registers, such as PIC and 6805 controllers. This is a solution was....
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This is a simple surround sound decoder. Left & right outputs of a stereo tape or CD player can be connected to the circuit inputs and 4 outputs of the circuit can be connected to a surround power amplifier or 2 stereo power amplifier. ..
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This converter allows reception of signals below 500 kHz on a 3.5 ? 4 MHz HF receiver. It should therefore be useful for those with receivers that do not receive the lower frequencies. Again the converter uses the popular NE602 mixer/oscillator chip. A cheap....
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The aim of this design was to reproduce a Combo amplifier of the type very common in the `sixties and the `seventies of the past century. It is well suited as a guitar amplifier but it will do a good job with any kind of electronic musical instrument or....
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This circuit is built around two chips: the MC1458 dual op amp, configured as a preamplifier, and the LM378 dual4-watt amplifier. The gain of the preamp is given by R3/R1 for one side and R4/R2 for the other side, which is about 100. That gain can be....
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The video switcher described here can display the output of two, three, or four cameras on a single monitor. The number of cameras is set by a DIP switch on the circuit board. That feature avoids blank displays if less than four cameras are used by....
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Tum on a game, computer, videodisc player, or whatever, and its output takes priority over the antenna-derived signal-the antenna is disconnected and the alternate source is fed to the monitor. When the alternate video source is no longer detected, the....
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A LED is defined as "light-emitting diode: diode such that light emitted at a p-n junction is proportional to the bias current; color depends on the material used" [Princeton University]. As the LED is a diode, it doesn't conduct electricity in both ways and....
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This line driver can drive low-impedance lines with up to 70 V p-p max. IC1 is a low-noise op amp suitable for 15-V operation. T1 and T2 are regulators for the power supply for IC1. T3 and T4 form a complementary power output stage...
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This is a collection of phono (black vinyl for the youngsters) preamps and equalisation circuits, one of which is sure to meet your requirements. These are not my circuits, but were contributed by a reader (see above), so I am not really in a position to....
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This amplifier is intended to be added to preamplifiers that have no phono input. Such a phono i..
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Figure 1 is a generalized block diagram of a multichemistry battery charger. A COP8ACC5 µC handles its key charging features. The µC is available in a 20-pin (15 I/O pins) SOIC or a 28-pin (23 I/O pins) SOIC/DIP. It contains 4 kbits of internal ROM...
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One v;ay to provide good negative-voltage regulation is with a low-dropout positive-voltage regulator operating from a well-isolated secondary winding of switch-mode circuit transformer. The technique works with any positive-voltage regulator, although....
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Most of the newer PIC come with the EUSART module which have the function for auto baud rate detection. The features allow a person to set the baud rate at runtime by sending the character "U" or 0x55 to the PIC. With ABDEN (auto baud rate enable) bit set....
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The pulser generates pulses at a user-selected frequency of 0.5 or 500 Hz, with a pulse width of about 5 ms. If the input to be pulsed is already being driven high or low by another output, the pulser automatically pulses the input to the opposite logic....
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Liquid crystal displays are currently available in several versions and various sizes. The wide variety of features, has resulted in there a little chaos in the provision of the pin. So that even when, after much effort, we can find a screen that fits our....
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A lot of friends me asked to draw a more shrunk circuit 2-ch mixer, which will contain also, operation CROSSFADER. The circuits can be modified and added also other channels, repeating basic that I give. It can are added channels stereo PHONO/line or even....
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A voltage window switch is in practice the basic lower window limit of this circuit is roughly 3V and the upper limit is 9V. The window range can be extended by fitting a suitable range
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This CW transmitter has an output of up to 3 W. By using 24 V on Q2, up to 10 W output can be obtained. If a 24-V supply is used, Ql must not see more than 12 V. Connect 12 V between junctions C3, R2 and L2, and remove L5. LI should be a low-Q 18- to 20-....
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A phase shift oscillator using the LM324 operates at an adjustable rate, 5-10 Hz, set by the speed pot. A portion of the oscillator output is taken from the depth pot and used to modulate the on resistance of two 1N914 diodes operating as voltage....
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An omnidirectional electret microphone can be used to pick up the sound and convert it into an electrical signal. The output of the microphone is fed along two paths. In the first path, the signal is sent to the inverting input at pin 6. In the second path,....
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The circuit requires only one dual-ganged potentiometer to tune over a wide range; if necessary over the entire audio range in one sweep. The principle used is that of the Wien bridge, fed from anti-phase inputs. The output should be buffered as shown with a....
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The adjustable voltage monitor can be used to check whether the voltage in a circuit remains within a given range. If the dc voltage is less than the voltage at pin 5 of-Ul-B, then LED 1 will light. If the voltage is over 5V, LED2 will light. If the voltage....
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The circuit is economical in components, and will work with virtually any transistors and is reliably self-starting. The voltage Vb can be taken from a divider, as shown at the right. If taken from a fixed source, flashing becomes slower as battery voltage....
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Designers who build equipment for the industrial market share a widespread problem. At one extreme, they must build equipment that supports ±10V bipolar voltages, often riding on a high common-mode level, a requirement enforced by 30 years of legacy....
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The proposed mixer is designed around four current-driven transconductance amplifiers contained in an SSM2024 from Precisio..
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A bar-graph LED driver is used to drive 10 LEDs to give a relative indication of moisture. The moisture probes are connec..
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The operating principle of the circuit is very simple. The first Led D1 is placed in series with the resistor R2 and diode D4.An only be lit this LED indicates that the battery is ypofortismeni. For this reason Led D1 is red. If the voltage is greater than....
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This type of charger couples RF from L2 to an external pickup coil. The pickup coil connects to a rectifier and battery to be charged. This idea is handy because no wire or contacts are required. L2 is 10T #24 wire and L3 is 10T #30 wire...
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Building a stable noise generator for audio-frequency purposes requires only a few components. The circuit in Figure 1 relies on linear-feedback shift registers and some simple software. An eight-pin Microchip (www.microchip.com) PIC12C508 controller (IC2)....
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Several integrated high-side current-sense amplifiers, such as the MAX4172 (Maxim Integrated Products, www.maxim-ic.com), make it easy to measure the current from a positive power supply. With a couple of resistors, these devices provide a ground-referenced....
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The circuit is used to indicate two different water temperature trip points by turning on LEDs when the temperatures are reached. The circuit is constructed around the LM2904 dual operational amplifier powered from the 12 V auto system. The thermistor is in....
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This battery saver circuit can automatically turn off a small piece of test equipment after a desired period of time, allowing you to leave your shop worry free.This circuit uses a CD4011IC to act as a simple timer. One section acts as an RC discharge timer....
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The continuity tester is for tracing wiring on printed circuit boards. It only consumes any appreciable power when the test leads are shorted, so no On/Off switch is used or required. The applied voltage at the test terminals is insufficient to turn on....
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In this application, the ICM7249 is configured as an hours-in-use meter and shows how many whole hours of line voltage have been applied. The 20-MD resistor and high-pass filtering allow ac line activation of the SIS input. This configuration, which is....
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This system can be used with 4-, 6-, or 8-cylinder automobiles. The timebase formed by IC5 is an oscillator th..
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This Circuit uses a CD40110BE, Up/Down Counter IC's. This IC is able to Source Each Segment with 25 mA, Giving a Very Nice Bright Display. The 7 Segment Displays MUST be a Common Cathode Type, as I have used here. All the UnMarked Resistors should be at....
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The telephone ring generator shown below generates the needed high voltage from a simple switching mode power supply (SMPS) which employs a CMOS Schmitt Trigger square wave oscillator, 10 mH inductor, high voltage switching transistor (TIP47 or other high....
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This is a beta release of the PIXpand project. The PIXpand which is a device that connects to a TI calculator and enable it to store and retreive data to and from Playstation Memory cards. I am making this beta release as I do not have the time to continue....
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The example program included with the PG2051 evaluation kit is a basic serial to parallel converter written in 8051 assembler. This is probably a good example of the uses to which an AT89C2051 can be put - it would be hard to get a serial to parallel....
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This is an early picture of my discolight effect. Because of the AGC circuit theres no need for potentionmeters for sensitivity adjust. I replaced them with trimmers. Now the microphone is on the control electronics because theres no need to place it outside....
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Anyone who has ever dealt with construction of low-voltage-fed inverter realized that this is no easy task. The shrinking supply voltage decreases rapidly transferred power and efficiency. Samokmitající converters fail to provide sufficient power to drive....
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The precision voltage-monitor chip contains a temperature-compensated voltage reference. R1 divides down the battery voltage to match the built-in reference voltage of ICl (15 volts). When the voltage at pin 3 falls below 15 volts, pin 4 supplies a constant....
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The design consists of differential compound pairs of transistors with a common mode (floating) gain control connecting the emitters of the pair. The compound pairs of 2N4403 and BC549s are far more linear than any single transistor. The circuit is....
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A shortcoming of the above bi-directional proportional motor control circuit is that with the potentiometer in its center position the motor does not stop, but creeps due to the difficulty in setting the potentiometer for an exact 1:1 mark-space ratio from....
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Pushing the button once will energize the relay. Pushing the same button a second time will de-energize the relay. Any simple momentary action push-to-make switch will do...
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The circuit is pretty simple. The data lines on the LCD match up well with the data lines of the parallel port, and extra parallel port I/O lines can be used to simulate the RS, R/W, and E signals on the LCD. The LCD module is pretty low-lower (with the....
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A tricolor LED, acts as the visual indicator of the voltage level. The voltage to be measured is connected to the two comparators in parallel. The first 20-KO trimmer defines a voltage between ±5 V and this becomes the full-scale value of the reference....
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Capacitor C 1 charges through resistor Rl, and when the gate level established by potentiometer R2 is high enough, the SCR is triggered. Current flows through the SCR and earphones, discharging Cl. The anode voltage and current drop to a low level, so....
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This active antenna schematic can be used to frequency range from 10 KHz to 100 MHz.
The length of the Antenna can be between 0.5 to 1 meter long. The power consumption is 20-30mA...
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This gauge uses a sensor in conjunction with R1 to develop a dc voltage proportional to oil pressure. IC1 and IC..
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This section describes an experimental low power, low bandwidth data signaling system that operates at 100 MHz (In the FM broadcast band in the U.S.). Before operating a radio transmitter, find out what kind of transmitter operation, if any, is permitted in....
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A milliohmmeter is just the tool for checking trace resistance on a printed circuit board, tracking down shorted traces, and measuring the contact resistance of a switch or connector. Its the kind of tool that would come in real handy occasionally, but not....
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This project is really a mixture of ideas, some simple, and others even simpler. The system I have installed in my biamp unit is fan cooling. Once a preset temperature is reached, the fans start, and remain on until the amp is turned off again. This is....
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The circuit is based on the TCM1506 ring detector/driver integrated circuit. It is a monolithic IC specifically designed to replace-the telephone`s mechanical bell. The chip is powered and activated by the telephone-line ring, which can vary from 40 to 150....
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Power Saving Using Time Operated Electrical Appliance Controlling System is a reliable circuit that takes over the task of switch on/off the electrical devices with respect to time. This project replaces the Manual Switching. It has an Inbuilt Real Time....
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The white-LED flasher in Figure 1 offers an alternative approach to a previously published idea (Reference 1). Targeting use in portable appliances and products powered by a single cell, this circuit flashes an LED to provide a highly visible warning....
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L1C1 are selected to be resonant at a frequency below the desired crystal harmonic but above the crystal"s next lower odd harmonic. C2 should have a value of 30-70 pF, independent of the oscillation frequency. There is no requirement for any specific ratio....
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The simple and inexpensive circuit in Figure 1 generates two PC-controlled analog reference voltages. You supply a wall-adapter supply and a parallel connector, and the circuit is ready to run. The circuit uses two 12-bit AD7243 DACs, which require only one....
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Basically, this circuit is an adjustable electronic circuit breaker, containing a toroidal transformer that senses 60-Hz load current. Tl has a two-turn winding for primary, and 100 turns of #30 gauge wire for the secondary. A high-low range switch selects....
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The IRPLCFL5E reference design is an electronic ballast for driving 26W compact fluorescent
lamps from 220VAC. The circuit provides all of the necessary functions for preheat, ignition and onstate
operation of the lamp and also includes the EMI filter and....
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This circuit is useful to amplify and distribute video signals with low noise and without losses. The CA3100 is a fast opamp designed to amplify video signals. Set the P1 to control the input signal level to have a clear picture on the TV set...
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Commutator circuit provides low impedance gate drive to the PN4091 analog switch for both on and off drive conditions..
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A bipolar input, high speed A/D converter uses two AM25L03s to form a 14-bit successive approximation register. The comparator is a two-stage circuit with an HA2605 front-end amplifier used to reduce settling time problems at the summing node..
This power supply is dedicated for use with rf equipments like, linear amplifiers, transmitters, receivers, and in every application that clean an-noisy signal is required. The circuit is very simple and you can drive it with a 220V/18V/3A transformer at the....
Stick the metal probes into a freshly watered plant and adjust R5 for a mid-scale meter deflection. The meter will monitor the soil wetness and the meter will indicate whether it is to moist or to dry. This circuit uses a dual power supply which could be....
The first circuit energizes the relay when the light rises above the preset level. The second circuit energizes the relay when the light falls below the preset level. The two circuits are practically identical. The only difference between them is the....
The circuit connects to the speaker outputs of your stereo or to the back of your speaker. The music passes through the transformer and the volume level is adjusted by the 5k ohm pot. Each light bulb is turn on by a different frequency of sound based on the....
The receiver chip uses a Panasonic 4602 38KHz receiver and that's it for external components. It has the serial input (GP3) , two RC hobby servo outputs (GP0/GP1) and three digital outputs (GP2,4,5). Here is the code for the receiver chip. It is a bit of a....
Some applications require a circuit to indicate that a battery`s voltage has fallen below a certain value. However, if you don`t frequently check the indicator, the low-battery indicator itself can easily discharge the battery. The circuit in Figure 1....
This circuit is about as good as it gets for generating morse code tones. It may be used as a code practice oscillator, a tone generator for a keyer, a sidetone oscillator for a CW transmitter or an audio Modulated CW (MCW) generator for an FM transmitter or....
Opening SA, changes the indicator lamp from flashing to steady-lit condition. The 6-V incandescent lamp on the collector of Q2 requires about 0.3 A. A 1-KO load resistor limits Ql"s collector current to about 6 mA. ..
High Quality unit with LM833 or NE5532 Low noise Dual Op-amp. No need for a preamplifier. # Can be directly connected to CD players, tuners and tape recorders. # Tested with several headphone models of different impedance: 32, 100, 245, 300, 600 & 2000....
This circuit is designed to work at UHF frequencies in the range 450-800MHz. It has a gain of around 10dB and is suitable for boosting weak TV signals. The circuit is shown below...
A Touch On/Off Switch is desired, this circuit fills the bill. Two sensitive gate SCRs are interconnected, so that when one of the devices is turned on, the other (if on) is forced off. That toggling effect gives an on/off circuit condition for each of the....
A Variable DC Power Supply is one of the most useful tools on the electronics hobbyist`s workbench. This circuit is not an absolute novelty, but it is simple, reliable, "rugged" and short-proof, featuring variable voltage up to 24V and variable current....
This circuit uses LEDs to display the beat frequency of two-tone oscillators. Only one LED is on at a time, and the apparent rotation of the dot is an exact indication of the best frequency..
There is enough of poorly constructed RS232 alike TTL level interfaces (+5volt) , this one generates it`s own +/- 10..11volts as RS232 specs. require , and is able to use very long cables like RS232 can , and protects computer as well , nice in funny....
In the absence of radiation, no current is drawn. At normal background radiation levels the power consumption is extremely low. The instrument may be left on for several months without changing batteries. In this way the detector is always ready to indicate....
This circuit uses the versatile MAX038 function generator. Although in this circuit some of the advanced characteristics of this IC are disabled, you can generate Sine, Triangle, Square waves (adjusting A0 and A1 pins see datasheet on www.maxim-ic.com if you....
The heart of the lock is the 40022 octal counter. When first powered C2 is charged via R5 so the reset input of the counter is kept high. That causes output Q to go high while all the other outputs are low. With the switches wired as shown, when S4 is....
PSU Designer II is designed to help you with the design of simple linear (unregulated) mains power supplies, as often found in tube amplifiers...
Originally I intended to have 32 faders. Once I tried fitting them on a veroboard, 32 seemed rather excessive so I have reduced to sixteen. This still allows generation of accurate eigth harmonic which compares well with the Hammond's ninth harmonic. A....
This Circuit is based on the LM3876. A 11-pin plastic package IC with high performance audio power amplifier, an output mute function which can be used to eliminate switch-on and switch-off "thumps" to the loudspeaker load. It is capable of delivering 40W....
The design incorporates 30-0, 1/4;.. microstrip lines on the input and output. C3, C4, C7, and C8, along with Ll, form a pi network that matches the low-input impedance of the device to 50 0. C5, C6, C9, ClO, and 30-0 transmission line L2 form an output pi....
This circuit may be used where a high current is required with a low ripple voltage (such as in a high powered class AB amplifier when high quality reproduction is necessary), Ql, Q2, and R2 may be regarded as a power darlington transistor. ZDl and Rl....
This article is about a software controlled, parallel port-interfacing 8-channel Pulse-Width-Modulated fan controller. I'll admit that the electronic part of it isn't very advanced, but hopefully the idea of "interfacing" might be interesting. My old....
This 3 channel 15 LED spectrum analyzer is the perfect addition to any audio amp project. It produces fantastic displays on three LED bars that can be individually adjusted for any particular frequency range. The circuit will take line level output from most....
You're simulating a circuit, it requires several digital gates, but you don't have a mixed-mode simulator. What to do? One solution involves creating simplified versions of the logic functions. To do this, we look to the NMOS transistor implementation of....
The circuit arrangement consists of a photo-amplifier which feeds a voltage derived from varying light levels in an enlarger to a pair of peak detectors. One follows the peak positive voltage and the other the peak negative voltage. The capacitors used for....
Just the solution for AVR applications in which I/O is tight, such as the ATtiny12. This should work well on other kids of controllers that have independently controlled I/O direction registers, such as PIC and 6805 controllers. This is a solution was....
This is a simple surround sound decoder. Left & right outputs of a stereo tape or CD player can be connected to the circuit inputs and 4 outputs of the circuit can be connected to a surround power amplifier or 2 stereo power amplifier. ..
This converter allows reception of signals below 500 kHz on a 3.5 ? 4 MHz HF receiver. It should therefore be useful for those with receivers that do not receive the lower frequencies. Again the converter uses the popular NE602 mixer/oscillator chip. A cheap....
The aim of this design was to reproduce a Combo amplifier of the type very common in the `sixties and the `seventies of the past century. It is well suited as a guitar amplifier but it will do a good job with any kind of electronic musical instrument or....
This circuit is built around two chips: the MC1458 dual op amp, configured as a preamplifier, and the LM378 dual4-watt amplifier. The gain of the preamp is given by R3/R1 for one side and R4/R2 for the other side, which is about 100. That gain can be....
The video switcher described here can display the output of two, three, or four cameras on a single monitor. The number of cameras is set by a DIP switch on the circuit board. That feature avoids blank displays if less than four cameras are used by....
Tum on a game, computer, videodisc player, or whatever, and its output takes priority over the antenna-derived signal-the antenna is disconnected and the alternate source is fed to the monitor. When the alternate video source is no longer detected, the....
A LED is defined as "light-emitting diode: diode such that light emitted at a p-n junction is proportional to the bias current; color depends on the material used" [Princeton University]. As the LED is a diode, it doesn't conduct electricity in both ways and....
This line driver can drive low-impedance lines with up to 70 V p-p max. IC1 is a low-noise op amp suitable for 15-V operation. T1 and T2 are regulators for the power supply for IC1. T3 and T4 form a complementary power output stage...
This is a collection of phono (black vinyl for the youngsters) preamps and equalisation circuits, one of which is sure to meet your requirements. These are not my circuits, but were contributed by a reader (see above), so I am not really in a position to....
This amplifier is intended to be added to preamplifiers that have no phono input. Such a phono i..
One v;ay to provide good negative-voltage regulation is with a low-dropout positive-voltage regulator operating from a well-isolated secondary winding of switch-mode circuit transformer. The technique works with any positive-voltage regulator, although....
Most of the newer PIC come with the EUSART module which have the function for auto baud rate detection. The features allow a person to set the baud rate at runtime by sending the character "U" or 0x55 to the PIC. With ABDEN (auto baud rate enable) bit set....
The pulser generates pulses at a user-selected frequency of 0.5 or 500 Hz, with a pulse width of about 5 ms. If the input to be pulsed is already being driven high or low by another output, the pulser automatically pulses the input to the opposite logic....
Liquid crystal displays are currently available in several versions and various sizes. The wide variety of features, has resulted in there a little chaos in the provision of the pin. So that even when, after much effort, we can find a screen that fits our....
A lot of friends me asked to draw a more shrunk circuit 2-ch mixer, which will contain also, operation CROSSFADER. The circuits can be modified and added also other channels, repeating basic that I give. It can are added channels stereo PHONO/line or even....
A voltage window switch is in practice the basic lower window limit of this circuit is roughly 3V and the upper limit is 9V. The window range can be extended by fitting a suitable range ..
This CW transmitter has an output of up to 3 W. By using 24 V on Q2, up to 10 W output can be obtained. If a 24-V supply is used, Ql must not see more than 12 V. Connect 12 V between junctions C3, R2 and L2, and remove L5. LI should be a low-Q 18- to 20-....
A phase shift oscillator using the LM324 operates at an adjustable rate, 5-10 Hz, set by the speed pot. A portion of the oscillator output is taken from the depth pot and used to modulate the on resistance of two 1N914 diodes operating as voltage....
An omnidirectional electret microphone can be used to pick up the sound and convert it into an electrical signal. The output of the microphone is fed along two paths. In the first path, the signal is sent to the inverting input at pin 6. In the second path,....
The circuit requires only one dual-ganged potentiometer to tune over a wide range; if necessary over the entire audio range in one sweep. The principle used is that of the Wien bridge, fed from anti-phase inputs. The output should be buffered as shown with a....
The adjustable voltage monitor can be used to check whether the voltage in a circuit remains within a given range. If the dc voltage is less than the voltage at pin 5 of-Ul-B, then LED 1 will light. If the voltage is over 5V, LED2 will light. If the voltage....
The circuit is economical in components, and will work with virtually any transistors and is reliably self-starting. The voltage Vb can be taken from a divider, as shown at the right. If taken from a fixed source, flashing becomes slower as battery voltage....
Designers who build equipment for the industrial market share a widespread problem. At one extreme, they must build equipment that supports ±10V bipolar voltages, often riding on a high common-mode level, a requirement enforced by 30 years of legacy....
The proposed mixer is designed around four current-driven transconductance amplifiers contained in an SSM2024 from Precisio..
A bar-graph LED driver is used to drive 10 LEDs to give a relative indication of moisture. The moisture probes are connec..
The operating principle of the circuit is very simple. The first Led D1 is placed in series with the resistor R2 and diode D4.An only be lit this LED indicates that the battery is ypofortismeni. For this reason Led D1 is red. If the voltage is greater than....
This type of charger couples RF from L2 to an external pickup coil. The pickup coil connects to a rectifier and battery to be charged. This idea is handy because no wire or contacts are required. L2 is 10T #24 wire and L3 is 10T #30 wire...
The circuit is used to indicate two different water temperature trip points by turning on LEDs when the temperatures are reached. The circuit is constructed around the LM2904 dual operational amplifier powered from the 12 V auto system. The thermistor is in....
This battery saver circuit can automatically turn off a small piece of test equipment after a desired period of time, allowing you to leave your shop worry free.This circuit uses a CD4011IC to act as a simple timer. One section acts as an RC discharge timer....
The continuity tester is for tracing wiring on printed circuit boards. It only consumes any appreciable power when the test leads are shorted, so no On/Off switch is used or required. The applied voltage at the test terminals is insufficient to turn on....
In this application, the ICM7249 is configured as an hours-in-use meter and shows how many whole hours of line voltage have been applied. The 20-MD resistor and high-pass filtering allow ac line activation of the SIS input. This configuration, which is....
This system can be used with 4-, 6-, or 8-cylinder automobiles. The timebase formed by IC5 is an oscillator th..
This Circuit uses a CD40110BE, Up/Down Counter IC's. This IC is able to Source Each Segment with 25 mA, Giving a Very Nice Bright Display. The 7 Segment Displays MUST be a Common Cathode Type, as I have used here. All the UnMarked Resistors should be at....
The telephone ring generator shown below generates the needed high voltage from a simple switching mode power supply (SMPS) which employs a CMOS Schmitt Trigger square wave oscillator, 10 mH inductor, high voltage switching transistor (TIP47 or other high....
This is a beta release of the PIXpand project. The PIXpand which is a device that connects to a TI calculator and enable it to store and retreive data to and from Playstation Memory cards. I am making this beta release as I do not have the time to continue....
The example program included with the PG2051 evaluation kit is a basic serial to parallel converter written in 8051 assembler. This is probably a good example of the uses to which an AT89C2051 can be put - it would be hard to get a serial to parallel....
This is an early picture of my discolight effect. Because of the AGC circuit theres no need for potentionmeters for sensitivity adjust. I replaced them with trimmers. Now the microphone is on the control electronics because theres no need to place it outside....
Anyone who has ever dealt with construction of low-voltage-fed inverter realized that this is no easy task. The shrinking supply voltage decreases rapidly transferred power and efficiency. Samokmitající converters fail to provide sufficient power to drive....
The precision voltage-monitor chip contains a temperature-compensated voltage reference. R1 divides down the battery voltage to match the built-in reference voltage of ICl (15 volts). When the voltage at pin 3 falls below 15 volts, pin 4 supplies a constant....
The design consists of differential compound pairs of transistors with a common mode (floating) gain control connecting the emitters of the pair. The compound pairs of 2N4403 and BC549s are far more linear than any single transistor. The circuit is....
A shortcoming of the above bi-directional proportional motor control circuit is that with the potentiometer in its center position the motor does not stop, but creeps due to the difficulty in setting the potentiometer for an exact 1:1 mark-space ratio from....
Pushing the button once will energize the relay. Pushing the same button a second time will de-energize the relay. Any simple momentary action push-to-make switch will do...
The circuit is pretty simple. The data lines on the LCD match up well with the data lines of the parallel port, and extra parallel port I/O lines can be used to simulate the RS, R/W, and E signals on the LCD. The LCD module is pretty low-lower (with the....
A tricolor LED, acts as the visual indicator of the voltage level. The voltage to be measured is connected to the two comparators in parallel. The first 20-KO trimmer defines a voltage between ±5 V and this becomes the full-scale value of the reference....
Capacitor C 1 charges through resistor Rl, and when the gate level established by potentiometer R2 is high enough, the SCR is triggered. Current flows through the SCR and earphones, discharging Cl. The anode voltage and current drop to a low level, so....
This active antenna schematic can be used to frequency range from 10 KHz to 100 MHz. The length of the Antenna can be between 0.5 to 1 meter long. The power consumption is 20-30mA...
This gauge uses a sensor in conjunction with R1 to develop a dc voltage proportional to oil pressure. IC1 and IC..
This section describes an experimental low power, low bandwidth data signaling system that operates at 100 MHz (In the FM broadcast band in the U.S.). Before operating a radio transmitter, find out what kind of transmitter operation, if any, is permitted in....
A milliohmmeter is just the tool for checking trace resistance on a printed circuit board, tracking down shorted traces, and measuring the contact resistance of a switch or connector. Its the kind of tool that would come in real handy occasionally, but not....
This project is really a mixture of ideas, some simple, and others even simpler. The system I have installed in my biamp unit is fan cooling. Once a preset temperature is reached, the fans start, and remain on until the amp is turned off again. This is....
The circuit is based on the TCM1506 ring detector/driver integrated circuit. It is a monolithic IC specifically designed to replace-the telephone`s mechanical bell. The chip is powered and activated by the telephone-line ring, which can vary from 40 to 150....
Power Saving Using Time Operated Electrical Appliance Controlling System is a reliable circuit that takes over the task of switch on/off the electrical devices with respect to time. This project replaces the Manual Switching. It has an Inbuilt Real Time....
L1C1 are selected to be resonant at a frequency below the desired crystal harmonic but above the crystal"s next lower odd harmonic. C2 should have a value of 30-70 pF, independent of the oscillation frequency. There is no requirement for any specific ratio....
Basically, this circuit is an adjustable electronic circuit breaker, containing a toroidal transformer that senses 60-Hz load current. Tl has a two-turn winding for primary, and 100 turns of #30 gauge wire for the secondary. A high-low range switch selects....
This circuit is useful to amplify and distribute video signals with low noise and without losses. The CA3100 is a fast opamp designed to amplify video signals. Set the P1 to control the input signal level to have a clear picture on the TV set...
Commutator circuit provides low impedance gate drive to the PN4091 analog switch for both on and off drive conditions..
A bipolar input, high speed A/D converter uses two AM25L03s to form a 14-bit successive approximation register. The comparator is a two-stage circuit with an HA2605 front-end amplifier used to reduce settling time problems at the summing node..
