New Circuits Page 211
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The cross compiler works on any host supported by GNU tools (Solaris, GNU/Linux, FreeBSD, HP/UX, MacOS X, Windows,...)...
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The circuit in Figure 1 shows how a thermistor applies temperature compensation to the circuit`s output-current limit.
The MAX1714`s linear current-limit (ILIM) input range at Pin 6 of IC1 spans 0.5 to 2V, which corresponds to current-limit thresholds of....
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The method in Figure 1a needs no access or knowledge of the communicating devices. A C program opens two COM ports and installs interrupt-service routines for IRQ4 and IRQ3. Upon the reception of an interrupt, the routine stores a byte in a common circular....
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You can easily improve on a previous Design Idea to produce a slightly simpler resistor arrangement with better timing balance between switches, using a single resistor value (Reference 1, Figure 1). The use of a single resistor value, RS, in a series chain....
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This unity-gain follower amplifier has a CMOS p-channel input, an npn second-gain stage, and a CMOS inverter output. The IC building blocks are two CA3600E"s (CMOS transistor pairs) and a CA3046 npn transistor array. A zener-regulated leg provides bias for....
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The Tutorial shows how to interface 7-segment display to a microcontroller. Also explains how do display more than one 7-segment on same data lines using scanning method. 7 Seg displays are are basically 7 LED's. It will be much easier to understand if you....
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Most audio amplifier systems must have preamplifiers with many different characteristics. These include high-gain linear response for magnetic microphones, low-gain linear response for tuners, and high-gain RIAA equalization for magnetic phone cartridges. To....
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Ql is connected as an emitter follower in order to present a high input impedance to the guitar. C2, being a relatively low capacitance, cuts out most of the bass, and C3 with RV1 acts as a simple tone control to cut the treble, and hence the amount of....
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The circuit generates a warble-tone alarm signal that simulates the sound of a British police siren. IC1 is wired as an alarm generator and IC2 is wired as a 1 Hz astable multivibrator. The output of IC2 is used to frequency modulate IC1 via R5...
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This simple charger uses a single transistor as a constant current source. The voltage across
the pair of 1N4148 diodes biases the base of the BD140 medium power transistor. The base-
emitter voltage of the transistor and the forward voltage drop across....
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The Greinacher doubler circuit (a) transforms a grounded AC voltage (peak voltage Up) into symmetrical DC voltages of 1x Up each, thus producing 2x Up between outputs. If the input voltage is already symmetrical (e.g. as in an Obit), the Greinacher circuit....
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This firmware is intended to run on an Atmel ATtiny2313 operating from a 4, 8, 10, 16, or 20 MHz clock or an AT90S2313 operating from a 4 MHz clock. As far as I have been able to determine, the ATtiny2313 and AT90S2313 versions are interchangeable, and the....
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The circuit, a general-purpose system with many uses, vocalizes 59 allophones contained in the speech processor. After filtering and amplification, its pulse-code-modulated output can drive an 8-!l speaker. The processor"s address pins, Al to A6, define 64....
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You sometimes need to drive a white LED from one 1.5V battery. Unfortunately, the forward voltage of a white LED is 3 to 4V. So, you would need a dc/dc converter to drive the LED from one battery. Using the simple circuit in Figure 1, you can drive one white....
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You can use a single-supply system to precisely measure the temperature at a remote location with less than 1°C error over a 0 to 100°C range (Figure 1). The circuit includes T1, a low-cost AD590 temperature sensor; IC1, an AD8541 rail-to-rail amplifier;....
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A little board with most of Microchip kit, but less parts then all these boards. Only the basic components to get the microcontroller up and running the Microchip USB Library examples. PIC18F14K50 is a really basic device and after some research I found what....
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Fortunately, my trusty Arduino came to the rescue I created an Arduino-based AVR programmer that uses the high voltage programming mode and can fix pesky fuses like RSTDISBL. The Arduino has just enough IO to implement the entire HV protocol plus a go”....
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The Zen (single-ended MOSFET) amplifier was published by Nelson Pass in The Audio Amateur 1. In a subsequent issue of this magazine, Nelson slightly improved the original design 2. I decided to build the "Revisited" version with the following circuit....
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The circuit of graphic equalizer, allocates ten adjusting potesometer , that each one from them affects in a predetermined area of frequencies, the central frequency of which abstains a octave (double), from the central frequencies of her neighbouring....
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2 versions of the equalization circuit, the first having 6 db less insertion loss than the other. However, some may not be able to find a .68 microfarad capacitor. The second version uses a more common .22 microfarad capacitor. Both of these circuits operate....
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Switched-capacitor filters that are preset for a given bandwidth sometimes do not deliver the bandwidth or Q an application requires. By inverting the clock between two switched-capacitor bandpass filters, such as the MSFS1 from Mixed Signal Integration....
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This application note describes a low-cost circuit that can detect when a chassis fan filter has become clogged
with dust. It does this by using a temperature sensor to determine the rate of cooling of a transistor in the air
path of the cooling fan,....
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In Fig.1 see a DC current ? sensing switch, in which the current is applied from an 8 to 16 Volt supply. The R1 value is chosen so that it generates roughly 100 mV at the required trip current. In Fig. 2 shows how the above circuit can be made to act as a....
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Using a single cable such as speaker wire or doorbell cable, this circuit can be remotely positioned, for
example, at the bottom of a garden or garage, and used to detect all sound in that area. The cable can
be buried in a hosepipe or duct and is....
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This simple circuit is a good solution to the powering a dual supply op amp from a single battery problem. The circuit simply takes a positive voltage and inverts it. It uses only one 555 timer and a few other passive components, so it doesn`t add much in....
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In both circuits, the SCR (and thereby the lamp) can be latched on by momentarily closing SI, thereby fe..
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Here is a circuit of a remote control unit which makes use of the radio frequency signals to control various electrical appliances. This remote control unit has 4 channels which can be easily extended to 12. This circuit differs from similar circuits in view....
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The NE5561 provides pulse-proportional drive and speed control based on de tachometer feedback. This simple switching circuit consists of transistor 2N4920 pnp with a commutation diode used to deliver programmed pulse energy to the motor. A frequency of....
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This circuit can accept positive or negative or differential control voltages. The output frequency is zero when the control voltage is zero. The 741 op amp forms a current source controlled by the voltage Ec to charge the timing capacitor C1linearly.....
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Integrated circuit Ul is connected as a low-frequency asymmetrical oscillator. Its output is inverted by Ql and fed to the reset te..
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The circuit allows you to eliminate the vocal portion of an audio signal, while leaving the instru mental portion. The circuit mixes two channels that must be 180° out of phase, so the signals that form the center-stereo image is canceled out. Those....
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By utilizing both halves of the dual timer it is possible to obtain sequential timing. By connecting the output of the first half to the input of the second half via a 01 µ-F coupling capacitor, sequential timing may be obtained. Delay ti is determined by....
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There are applications where a particular band, or spread, or frequencies need to be filtered from a wider range of mixed signals. Filter circuits can be designed to accomplish this task by combining the properties of low-pass and high-pass into a single....
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The simplified circuit [Fig.2] shows that each sub-amplifier consists of two voltage gain stages. The first stage consists of a complementary two stage common emitter [Q1-7] whose gain is about x2.3. The second stage is a current mirror stage [Q13-14] which....
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You can use this circuit with any walkman or CD player since it is designed to take a standard 500mv RMS signal. A 15 watt amplifier made using discrete components. Sergio designed this circuit for his Electronics Level II course. This amplifier uses a dual....
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Designers can build a 15-dB compressor with a miniature lamp and a current-feedback amplifier. The circ..
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For the regulation it needs a voltmeter (with needle better) and charge 50W/5W. Connect charge 50W in the place of aerial, with the voltmeter in the exit voltmeter. Be supplied the transmitter with + 12V. It will be supposed we have consumption between....
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The diagram of detail of Fig.2 gives additional precise details: The signal HF collected by the antenna is amplified by T1, framed reel S of agreement L1 and L2. To vary the profit of T1, it is enough to vary its supply voltage. Here it passes from 4v to....
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Using an ISD1016 audio record/playback chip (Information Storage Devices, Inc.), this circuit records and plays back messages on command. Although intended for use with transmitters, it can be used as an electronic notepad, etc. ..
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When the touch-on contacts are bridged, pin 6 of Ul-b goes low, which forces its output (the set output) at pin 4 to go high. That high divides along two paths; in one path, the output is applied to pin 2 of Ul-a, which causes its output at pin 3 to go low.....
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T1 steps down AC voltage from 115VAC (or 220VAC) to about 8VAC and is then rectified via bridge rectifier BR1 to about 11.52Vdc. C1 filters off the AC ripple. If you find the circuit output too noisy add another electrolytic capacitor over the output....
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This simple adapter uses an oscillator (567) to drive a counter (U2) and switch (U3) that selects the outpu..
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Using modulated rectangular waves of different time periods, The circuit presented here produces ringing tones similar to those produced by a telephone.
The circuit requires four astable multivibrators for its working. Therefore two 556 ICs are used here.....
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This circuit is based around HT?2050 manufactured by HOLTEK semiconductors. It is a low cost, low-power C-MOS LSI designed for lamp andLED flash driver. It requires minimum external components.You can operate it with just two AAA cell or 3v Battery.Circuit....
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Here is a handy gadget for test- ing of infrared (IR) based re- mote control transmitters used for TVs and VCRs etc. The IR signals from a remote control transmitter are sensed by the IR sensor module in the tester and its output at pin 2 goes low. This in....
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This LOGIC PULSER capable of delivering pulses of various compositions, to any type of circuit you wish to test.
Basically it is designed to complement the LOGIC PROBE and can be used in situations where the LOGIC PROBE is not so effective.
It is an....
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Transistors Q1 and Q2 form a buffer, providing the probe with a reasonable input impedance. Q3 and Q4 form a level detecting circuit. As the voltage across the base-emitter junction of the Q3 rises above 0,6 V the transistor turns on thus turning on Q4 and....
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Using this circuit, tiiree levels of voltage can be displayednormal (11 to 15 V), liigh (>15 V), and low (11 V). When the voltage is low, the LED glows steadily. In the normal range, the LED is off. When the voltage is high, the LED blinks at a 1-Hz rate. ..
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When switching loads with the aid of a thyristor, a large amount of RFI can be generated unless some form of zero crossing switch is used. The circuit shows a simple single transistor zero crossing switch. Rl and R2 act as a potential divider. The potential....
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This Circuit is a zero crossing detector, which produces an output state change whenever the input crosses the reference input. In this case the reference input is connected to ground. The output of the comparator can easily drive multiple outputs, which can....
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The LA9472A is a 2A monolithic step down switching regulator operating in continuous mode and realized in a new BCD technology allowing the integration of isolated, vertical DMOS power transistors with mixed CMOS/bipolar transistors. The device can deliver....
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Using a switch to power up your microcontroller projects may not be a good idea if you need to "wake" the PIC during some events. For example: A metal detector sends a pulse indicating a car is ready to enter into a garaje, so the user needs to type a....
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The circuit, is a comparator, can measure with step of 1Volt, the voltage of battery of car. The clue of voltage become after comparison of voltage of battery, that is applied in the inverting inputs of amplifiers, with voltages of reference that are....
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The schematic of the SAVER V3.2 is depicted in Figure 1.A transformerless power supply uses Xc of a 0.22uF capacitor to limit current providing about 10mA current source. The diodes rectifies ac current to dc current which in turns charged to filtering....
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Security is a prime concern in our day-today life. Everyone wants to be as much secure as possible. An access control for doors forms a vital link in a security chain. The microcontroller based digital lock for Doors is an access control system that allows....
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The load`s power factor, which is the cosine of the phase angle between the voltage across the load current, can be calculated simply with this circuit. A1:1 isolation transformer is used to prevent direct contact with the line. By properly adjusting Rr,....
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The on-hook (no load) voltage across the red-green wires will be 48 V or slightly less when all telephones are on-hook (disconnected). When any telephone goes off-hook the load current flowing in the telephone causes the voltage to fall below 5 volts dc.....
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This circuit is so sensitive it will detect "mains hum." Simply move it across any wall and it will detect where the mains cable is located. It has a gain of about 200 x 200 x 200 = 6,000,000 and will also detect static electricity and the presence of your....
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This unique circuit makes your dome light look cool. Usually when the car door is closed, the dome light just goes OFF. With this circuit, you can have our dome light fade slowly in brightness and finally go OFF. This slow dimming of the light gives a very....
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The circuit in Figure 1 provides 32 steps of brightness controlfrom 0 to 100%for a backlight or instrument panel, using just two general-purpose-microprocessor signals. In addition, the circuit requires little board space, because it uses only three SOT-23s....
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Ql, Q2, and the associated circuitry form a modified astable multivibrator in which the loop gain is automatically adjusted to the threshold of oscillation by means of field effect transistor Q3. Q4 linearly amplifies the signal present at the collector of....
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The signal from a synchro receiver or a variable resistive cam follower (potentiometer) is boosted by operational amplifier Ul, whose output swing is limited by back-to-back zeners D3 and D4. The signal is then applied to operational amplifiers U2 and U3,....
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The mercury-in-rubber strain gauge is the detector of breathing. In the model device, the strain gauge produced by Medimatic, Demark was used. The change in the length of the strain gauge wrapped around the chest during breathing causes a varying....
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This phase-shift oscillator is useful for audio oscillator applications. Adjust R7 for a good sine w..
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The tester consists of a rectifier circuit and a multivibrator circuit. The ac voltage is half-wave rectified by diode D1 and stored in capacitor CI. Resistor Rl is used to limit the current through D1 to a safe value. The voltage stored across CI supplies....
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At VHF, both the 1/4-wavelength monopole and the 5/8-wavelength monopole antennas are widely used. The VHF 5/8-wavelength (144 Mhz) vertical monopole has long held the reputation of providing about a 3-dB gain advantage over the 1/4-wavelength vertical....
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No description available...
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The LTC1685 is geared for half-duplex operation, whereas
the LTC1686/LTC1687 can operate in full-duplex mode. All
include a receiver fail-safe feature, whereby the receiver
output remains in a high state over the entire 12V to 7V
common mode range when....
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The RS485 interface standard is designed to handle a 7V
to 12V input signal range; however, in practical systems,
ground potentials vary widely from node to node, often
exceeding the specified range. This can result in an
interruption of communications,....
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Three 555 IC timers are used in this circuit to construct a simple delayed-pulse generator. IC1 acts as a waveform shaper to produce a rectangular waveform. IC2 produces a delaying pulse to trigger 103 on the trailing edge of the delaying pulse. Rl controls....
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A relay-based on/off controller on the other hand can be very efficient. A typical relay has a contact resistance of 3 milliOhm. At 20A, this translates to a voltage drop of 0.06 volts, with a power loss of 1.2W. The relay itself typically consumes around....
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This photocell is best mounted at tie level between the rails. The variable resistor adjusts the sensitivity of the circuit. This circuit can be powered by either 6 or 12 volts - BE SURE to use the proper relay;..
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The choice of material to read or drive is the definition of three digits (Bit), RA0, 1,2 PORTA of the PIC at the entrance of 74HC138A. To select a material for reading or driving an output of 78HC138 is '0 '(Low), forcing the transistor (2SA1015) to conduct....
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A zener diode placed in series with a voltmeter will prevent the meter from reading until the applied voltage exceeds the zener voltage..
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IR appliances use pulses (control signals) sent over a modulated IR carrier wave. The carrier wave may be modulated at various frequencies, 36-38KHz being the most popular.Some Satellite receivers use even higher frequencies than this. The IR1 remote module....
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A 1-V amplitude pulse triggers SCSl, but has insufficient amplitude to trigger SCS2. A 3-V input pulse is delayed in reaching SCSl by the 10-KO and .001-!"F integrating network. Instead, it triggers SCS2, then raises the common emitter voltage to prevent....
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The basic requirements than one laboratory power supply, it is to provide voltages and currents of operation that need the usual units, to have low output resistance, low noise, small ripple and good stabilization. The above requirements are covered, from....
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Transistor Ql remains off until the magnetic switch connected to Jl closes. When that happens, the 9 Vis connected through Rl to Ql"S base. Ql turns on, thereby charging C2 through relay Kl, which causes Kl "s contacts to close. Since the contacts connect....
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This is a simple microphone preamplifier circuit which you can use between your dynamic microphone and any equipment designed to work with an electret microhone (2 wire connection to electret capsule). This amplifier amplifies the low level signal to the....
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The heart of the Chloroplast is the Motorola MC34164-3 Micro power Undervoltage Sensing Circuit (U1 in the following diagram). In normal use, this component monitors the voltage at pin 2, and applies a ground at pin 1 ( out ) when the monitored voltage drops....
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Universal motors and shade d-pole induction motors can be easily controlled with a full-wave Triac speed controller. Q1 combines both the triac and diac trigger diodes in the same case. The motor used for the load must be limited to 6 amperes maximum. Triac....
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This circuit is intended to provide good square waves converting a sine wave picked-up from an existing generator. Its main feature consists in the fact that no power-source is needed: thus it can be simply connected between a sine wave generator and the....
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I was originally going to develop a minimum part count version of the EH Electric Mistress. Instead I went for a something with the versatility of an MXR flanger and the extra wide sweep that the A/DA flanger was known for. It needed an extra chip to get the....
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The arc welder simulator is made up from several functional blocks: five oscillators, two gates and the output driver.
IC1A, IC1B and IC1C are all wired as square wave oscillators, each operating at a different frequency under 100 Hz. This output is a pulse....
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The traditional restnct1on of constant gainbandwidth products for a voltage amplifier can be overcome by employing feedback around a current amplifier. Two current mirrors, constructed from transistors in a CA3096AE array, effectively turn the LF351 op amp....
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The circuit is a simple op-amp but with two diodes (the transistor b-e junctions in the feedback to split the feedback for positive and negative outputs. On positive output from the stepper coil the top transistor tuns on, on negative, the bottom. One or....
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The Unit is started by hand by revolving the two disks in opposite directions and continues to move without further input.
This device has only two moving parts namely the bearing races at the centre of the disk.
The disk are made of clear plastic upon....
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This is the simplest of any programmable oscil lator circuit, since only one stable timing capacitor is required. The output square wave is about 25 V pk-pk, and bas rise and fall times of about 0.5 p,s. ..
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The circuit consists of an ICM7208 seven-decade counter (Ul), an ICM7207A oscillator controller (U2), and a CA3130 biFET op amp (U3). Integrated circuit Ul counts input signals, decodes them to 7-segment format, and outputs signals that are used to drive a....
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The circuitry for a hot swappable PCI slot on a motherboard or backplane is shown in Figure 1. The power supplies for each PCI slot are controlled by an LTC1421 and four external FETs, and the data bus is buffered by several QS3384 QuickSwitches or....
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A magnetic loop has a very small bandwidth but unsensitive to man made noise. It is much smaller than a conventional antenna for the same frequency and has a gain that can be compared to a quarter wave antenna even if the loop is mounted a meter from the....
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In this circuit, a 74HC14 hex Schmitt trigger inverter is used as a square wave oscillator to drive a small signal transistor in a class C amplifier configuration. The oscillator frequency can be either fixed by a crystal or made adjustable (VFO) with a....
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This simple circuit using a single transistor turns ON the relay when light falls on the LDR.
The potentiometer is adjusted for the required sensitivity.
The power supply is 6V.
Be careful about the impedance of the relay. Its impedance should not be less....
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A useful operation for the cars is delayed extinguishing internal lighting cabin of passengers, after close some door of car. Certain cars allocate this operation from their constructor. Oldest sure do not allocate such operation. This delay makes this....
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White LEDs are popular for portable equipment LCD backlights because they are less complex, less expensive, and smaller than CCFL backlights. Portable equipment like PDAs, cellphones, and digital cameras require backlights because they are converting to....
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This Design Idea shows how you can use Linear Technology`s LTC6903 programmable oscillator as a clock source for direct-digital synthesis, data conversion, switched-capacitor filtering, clock, and voltage-controlled oscillator circuits...
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Take strobe-flash pictures the instant a pin pricks a balloon, a hammer breaks a lamp bulb or a bullet leaves a gun. Use a transistor amplifier of 1-watt rating or less. (It must have an output transformer) The amplifier is terminated with a resistor on its....
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Ul is an op amp used as a comparator. When the test probes are shorted together, resistors R1 and R2 bias the noninverti..
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This is a positioning servo drive featuring adjustment of balance, gain, and deadband. In addition to control from a dc signal, mechanical input can be fed into the balance control, or that control could be replaced by a pair of resistance transducers for....
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Create single, double-sided or multilayer PCBs of your circuits with a single mouse click, using automatically-placed and routed components. All components in TINA are "PCB-ready" and have associated footprints....
The cross compiler works on any host supported by GNU tools (Solaris, GNU/Linux, FreeBSD, HP/UX, MacOS X, Windows,...)...
This unity-gain follower amplifier has a CMOS p-channel input, an npn second-gain stage, and a CMOS inverter output. The IC building blocks are two CA3600E"s (CMOS transistor pairs) and a CA3046 npn transistor array. A zener-regulated leg provides bias for....
The Tutorial shows how to interface 7-segment display to a microcontroller. Also explains how do display more than one 7-segment on same data lines using scanning method. 7 Seg displays are are basically 7 LED's. It will be much easier to understand if you....
Most audio amplifier systems must have preamplifiers with many different characteristics. These include high-gain linear response for magnetic microphones, low-gain linear response for tuners, and high-gain RIAA equalization for magnetic phone cartridges. To....
Ql is connected as an emitter follower in order to present a high input impedance to the guitar. C2, being a relatively low capacitance, cuts out most of the bass, and C3 with RV1 acts as a simple tone control to cut the treble, and hence the amount of....
The circuit generates a warble-tone alarm signal that simulates the sound of a British police siren. IC1 is wired as an alarm generator and IC2 is wired as a 1 Hz astable multivibrator. The output of IC2 is used to frequency modulate IC1 via R5...
This simple charger uses a single transistor as a constant current source. The voltage across the pair of 1N4148 diodes biases the base of the BD140 medium power transistor. The base- emitter voltage of the transistor and the forward voltage drop across....
The Greinacher doubler circuit (a) transforms a grounded AC voltage (peak voltage Up) into symmetrical DC voltages of 1x Up each, thus producing 2x Up between outputs. If the input voltage is already symmetrical (e.g. as in an Obit), the Greinacher circuit....
This firmware is intended to run on an Atmel ATtiny2313 operating from a 4, 8, 10, 16, or 20 MHz clock or an AT90S2313 operating from a 4 MHz clock. As far as I have been able to determine, the ATtiny2313 and AT90S2313 versions are interchangeable, and the....
The circuit, a general-purpose system with many uses, vocalizes 59 allophones contained in the speech processor. After filtering and amplification, its pulse-code-modulated output can drive an 8-!l speaker. The processor"s address pins, Al to A6, define 64....
A little board with most of Microchip kit, but less parts then all these boards. Only the basic components to get the microcontroller up and running the Microchip USB Library examples. PIC18F14K50 is a really basic device and after some research I found what....
Fortunately, my trusty Arduino came to the rescue I created an Arduino-based AVR programmer that uses the high voltage programming mode and can fix pesky fuses like RSTDISBL. The Arduino has just enough IO to implement the entire HV protocol plus a go”....
The Zen (single-ended MOSFET) amplifier was published by Nelson Pass in The Audio Amateur 1. In a subsequent issue of this magazine, Nelson slightly improved the original design 2. I decided to build the "Revisited" version with the following circuit....
The circuit of graphic equalizer, allocates ten adjusting potesometer , that each one from them affects in a predetermined area of frequencies, the central frequency of which abstains a octave (double), from the central frequencies of her neighbouring....
2 versions of the equalization circuit, the first having 6 db less insertion loss than the other. However, some may not be able to find a .68 microfarad capacitor. The second version uses a more common .22 microfarad capacitor. Both of these circuits operate....
Switched-capacitor filters that are preset for a given bandwidth sometimes do not deliver the bandwidth or Q an application requires. By inverting the clock between two switched-capacitor bandpass filters, such as the MSFS1 from Mixed Signal Integration....
In Fig.1 see a DC current ? sensing switch, in which the current is applied from an 8 to 16 Volt supply. The R1 value is chosen so that it generates roughly 100 mV at the required trip current. In Fig. 2 shows how the above circuit can be made to act as a....
Using a single cable such as speaker wire or doorbell cable, this circuit can be remotely positioned, for example, at the bottom of a garden or garage, and used to detect all sound in that area. The cable can be buried in a hosepipe or duct and is....
This simple circuit is a good solution to the powering a dual supply op amp from a single battery problem. The circuit simply takes a positive voltage and inverts it. It uses only one 555 timer and a few other passive components, so it doesn`t add much in....
In both circuits, the SCR (and thereby the lamp) can be latched on by momentarily closing SI, thereby fe..
Here is a circuit of a remote control unit which makes use of the radio frequency signals to control various electrical appliances. This remote control unit has 4 channels which can be easily extended to 12. This circuit differs from similar circuits in view....
The NE5561 provides pulse-proportional drive and speed control based on de tachometer feedback. This simple switching circuit consists of transistor 2N4920 pnp with a commutation diode used to deliver programmed pulse energy to the motor. A frequency of....
This circuit can accept positive or negative or differential control voltages. The output frequency is zero when the control voltage is zero. The 741 op amp forms a current source controlled by the voltage Ec to charge the timing capacitor C1linearly.....
Integrated circuit Ul is connected as a low-frequency asymmetrical oscillator. Its output is inverted by Ql and fed to the reset te..
The circuit allows you to eliminate the vocal portion of an audio signal, while leaving the instru mental portion. The circuit mixes two channels that must be 180° out of phase, so the signals that form the center-stereo image is canceled out. Those....
By utilizing both halves of the dual timer it is possible to obtain sequential timing. By connecting the output of the first half to the input of the second half via a 01 µ-F coupling capacitor, sequential timing may be obtained. Delay ti is determined by....
There are applications where a particular band, or spread, or frequencies need to be filtered from a wider range of mixed signals. Filter circuits can be designed to accomplish this task by combining the properties of low-pass and high-pass into a single....
The simplified circuit [Fig.2] shows that each sub-amplifier consists of two voltage gain stages. The first stage consists of a complementary two stage common emitter [Q1-7] whose gain is about x2.3. The second stage is a current mirror stage [Q13-14] which....
You can use this circuit with any walkman or CD player since it is designed to take a standard 500mv RMS signal. A 15 watt amplifier made using discrete components. Sergio designed this circuit for his Electronics Level II course. This amplifier uses a dual....
Designers can build a 15-dB compressor with a miniature lamp and a current-feedback amplifier. The circ..
For the regulation it needs a voltmeter (with needle better) and charge 50W/5W. Connect charge 50W in the place of aerial, with the voltmeter in the exit voltmeter. Be supplied the transmitter with + 12V. It will be supposed we have consumption between....
The diagram of detail of Fig.2 gives additional precise details: The signal HF collected by the antenna is amplified by T1, framed reel S of agreement L1 and L2. To vary the profit of T1, it is enough to vary its supply voltage. Here it passes from 4v to....
Using an ISD1016 audio record/playback chip (Information Storage Devices, Inc.), this circuit records and plays back messages on command. Although intended for use with transmitters, it can be used as an electronic notepad, etc. ..
When the touch-on contacts are bridged, pin 6 of Ul-b goes low, which forces its output (the set output) at pin 4 to go high. That high divides along two paths; in one path, the output is applied to pin 2 of Ul-a, which causes its output at pin 3 to go low.....
T1 steps down AC voltage from 115VAC (or 220VAC) to about 8VAC and is then rectified via bridge rectifier BR1 to about 11.52Vdc. C1 filters off the AC ripple. If you find the circuit output too noisy add another electrolytic capacitor over the output....
This simple adapter uses an oscillator (567) to drive a counter (U2) and switch (U3) that selects the outpu..
Using modulated rectangular waves of different time periods, The circuit presented here produces ringing tones similar to those produced by a telephone. The circuit requires four astable multivibrators for its working. Therefore two 556 ICs are used here.....
This circuit is based around HT?2050 manufactured by HOLTEK semiconductors. It is a low cost, low-power C-MOS LSI designed for lamp andLED flash driver. It requires minimum external components.You can operate it with just two AAA cell or 3v Battery.Circuit....
Here is a handy gadget for test- ing of infrared (IR) based re- mote control transmitters used for TVs and VCRs etc. The IR signals from a remote control transmitter are sensed by the IR sensor module in the tester and its output at pin 2 goes low. This in....
This LOGIC PULSER capable of delivering pulses of various compositions, to any type of circuit you wish to test. Basically it is designed to complement the LOGIC PROBE and can be used in situations where the LOGIC PROBE is not so effective. It is an....
Transistors Q1 and Q2 form a buffer, providing the probe with a reasonable input impedance. Q3 and Q4 form a level detecting circuit. As the voltage across the base-emitter junction of the Q3 rises above 0,6 V the transistor turns on thus turning on Q4 and....
Using this circuit, tiiree levels of voltage can be displayednormal (11 to 15 V), liigh (>15 V), and low (11 V). When the voltage is low, the LED glows steadily. In the normal range, the LED is off. When the voltage is high, the LED blinks at a 1-Hz rate. ..
When switching loads with the aid of a thyristor, a large amount of RFI can be generated unless some form of zero crossing switch is used. The circuit shows a simple single transistor zero crossing switch. Rl and R2 act as a potential divider. The potential....
The LA9472A is a 2A monolithic step down switching regulator operating in continuous mode and realized in a new BCD technology allowing the integration of isolated, vertical DMOS power transistors with mixed CMOS/bipolar transistors. The device can deliver....
Using a switch to power up your microcontroller projects may not be a good idea if you need to "wake" the PIC during some events. For example: A metal detector sends a pulse indicating a car is ready to enter into a garaje, so the user needs to type a....
The circuit, is a comparator, can measure with step of 1Volt, the voltage of battery of car. The clue of voltage become after comparison of voltage of battery, that is applied in the inverting inputs of amplifiers, with voltages of reference that are....
The schematic of the SAVER V3.2 is depicted in Figure 1.A transformerless power supply uses Xc of a 0.22uF capacitor to limit current providing about 10mA current source. The diodes rectifies ac current to dc current which in turns charged to filtering....
Security is a prime concern in our day-today life. Everyone wants to be as much secure as possible. An access control for doors forms a vital link in a security chain. The microcontroller based digital lock for Doors is an access control system that allows....
The load`s power factor, which is the cosine of the phase angle between the voltage across the load current, can be calculated simply with this circuit. A1:1 isolation transformer is used to prevent direct contact with the line. By properly adjusting Rr,....
The on-hook (no load) voltage across the red-green wires will be 48 V or slightly less when all telephones are on-hook (disconnected). When any telephone goes off-hook the load current flowing in the telephone causes the voltage to fall below 5 volts dc.....
This circuit is so sensitive it will detect "mains hum." Simply move it across any wall and it will detect where the mains cable is located. It has a gain of about 200 x 200 x 200 = 6,000,000 and will also detect static electricity and the presence of your....
This unique circuit makes your dome light look cool. Usually when the car door is closed, the dome light just goes OFF. With this circuit, you can have our dome light fade slowly in brightness and finally go OFF. This slow dimming of the light gives a very....
Ql, Q2, and the associated circuitry form a modified astable multivibrator in which the loop gain is automatically adjusted to the threshold of oscillation by means of field effect transistor Q3. Q4 linearly amplifies the signal present at the collector of....
The signal from a synchro receiver or a variable resistive cam follower (potentiometer) is boosted by operational amplifier Ul, whose output swing is limited by back-to-back zeners D3 and D4. The signal is then applied to operational amplifiers U2 and U3,....
The mercury-in-rubber strain gauge is the detector of breathing. In the model device, the strain gauge produced by Medimatic, Demark was used. The change in the length of the strain gauge wrapped around the chest during breathing causes a varying....
This phase-shift oscillator is useful for audio oscillator applications. Adjust R7 for a good sine w..
The tester consists of a rectifier circuit and a multivibrator circuit. The ac voltage is half-wave rectified by diode D1 and stored in capacitor CI. Resistor Rl is used to limit the current through D1 to a safe value. The voltage stored across CI supplies....
At VHF, both the 1/4-wavelength monopole and the 5/8-wavelength monopole antennas are widely used. The VHF 5/8-wavelength (144 Mhz) vertical monopole has long held the reputation of providing about a 3-dB gain advantage over the 1/4-wavelength vertical....
Three 555 IC timers are used in this circuit to construct a simple delayed-pulse generator. IC1 acts as a waveform shaper to produce a rectangular waveform. IC2 produces a delaying pulse to trigger 103 on the trailing edge of the delaying pulse. Rl controls....
A relay-based on/off controller on the other hand can be very efficient. A typical relay has a contact resistance of 3 milliOhm. At 20A, this translates to a voltage drop of 0.06 volts, with a power loss of 1.2W. The relay itself typically consumes around....
This photocell is best mounted at tie level between the rails. The variable resistor adjusts the sensitivity of the circuit. This circuit can be powered by either 6 or 12 volts - BE SURE to use the proper relay;..
The choice of material to read or drive is the definition of three digits (Bit), RA0, 1,2 PORTA of the PIC at the entrance of 74HC138A. To select a material for reading or driving an output of 78HC138 is '0 '(Low), forcing the transistor (2SA1015) to conduct....
A zener diode placed in series with a voltmeter will prevent the meter from reading until the applied voltage exceeds the zener voltage..
IR appliances use pulses (control signals) sent over a modulated IR carrier wave. The carrier wave may be modulated at various frequencies, 36-38KHz being the most popular.Some Satellite receivers use even higher frequencies than this. The IR1 remote module....
A 1-V amplitude pulse triggers SCSl, but has insufficient amplitude to trigger SCS2. A 3-V input pulse is delayed in reaching SCSl by the 10-KO and .001-!"F integrating network. Instead, it triggers SCS2, then raises the common emitter voltage to prevent....
The basic requirements than one laboratory power supply, it is to provide voltages and currents of operation that need the usual units, to have low output resistance, low noise, small ripple and good stabilization. The above requirements are covered, from....
Transistor Ql remains off until the magnetic switch connected to Jl closes. When that happens, the 9 Vis connected through Rl to Ql"S base. Ql turns on, thereby charging C2 through relay Kl, which causes Kl "s contacts to close. Since the contacts connect....
This is a simple microphone preamplifier circuit which you can use between your dynamic microphone and any equipment designed to work with an electret microhone (2 wire connection to electret capsule). This amplifier amplifies the low level signal to the....
The heart of the Chloroplast is the Motorola MC34164-3 Micro power Undervoltage Sensing Circuit (U1 in the following diagram). In normal use, this component monitors the voltage at pin 2, and applies a ground at pin 1 ( out ) when the monitored voltage drops....
Universal motors and shade d-pole induction motors can be easily controlled with a full-wave Triac speed controller. Q1 combines both the triac and diac trigger diodes in the same case. The motor used for the load must be limited to 6 amperes maximum. Triac....
This circuit is intended to provide good square waves converting a sine wave picked-up from an existing generator. Its main feature consists in the fact that no power-source is needed: thus it can be simply connected between a sine wave generator and the....
I was originally going to develop a minimum part count version of the EH Electric Mistress. Instead I went for a something with the versatility of an MXR flanger and the extra wide sweep that the A/DA flanger was known for. It needed an extra chip to get the....
The arc welder simulator is made up from several functional blocks: five oscillators, two gates and the output driver. IC1A, IC1B and IC1C are all wired as square wave oscillators, each operating at a different frequency under 100 Hz. This output is a pulse....
The traditional restnct1on of constant gainbandwidth products for a voltage amplifier can be overcome by employing feedback around a current amplifier. Two current mirrors, constructed from transistors in a CA3096AE array, effectively turn the LF351 op amp....
The circuit is a simple op-amp but with two diodes (the transistor b-e junctions in the feedback to split the feedback for positive and negative outputs. On positive output from the stepper coil the top transistor tuns on, on negative, the bottom. One or....
The Unit is started by hand by revolving the two disks in opposite directions and continues to move without further input. This device has only two moving parts namely the bearing races at the centre of the disk. The disk are made of clear plastic upon....
This is the simplest of any programmable oscil lator circuit, since only one stable timing capacitor is required. The output square wave is about 25 V pk-pk, and bas rise and fall times of about 0.5 p,s. ..
The circuit consists of an ICM7208 seven-decade counter (Ul), an ICM7207A oscillator controller (U2), and a CA3130 biFET op amp (U3). Integrated circuit Ul counts input signals, decodes them to 7-segment format, and outputs signals that are used to drive a....
The circuitry for a hot swappable PCI slot on a motherboard or backplane is shown in Figure 1. The power supplies for each PCI slot are controlled by an LTC1421 and four external FETs, and the data bus is buffered by several QS3384 QuickSwitches or....
In this circuit, a 74HC14 hex Schmitt trigger inverter is used as a square wave oscillator to drive a small signal transistor in a class C amplifier configuration. The oscillator frequency can be either fixed by a crystal or made adjustable (VFO) with a....
This simple circuit using a single transistor turns ON the relay when light falls on the LDR. The potentiometer is adjusted for the required sensitivity. The power supply is 6V. Be careful about the impedance of the relay. Its impedance should not be less....
A useful operation for the cars is delayed extinguishing internal lighting cabin of passengers, after close some door of car. Certain cars allocate this operation from their constructor. Oldest sure do not allocate such operation. This delay makes this....
Take strobe-flash pictures the instant a pin pricks a balloon, a hammer breaks a lamp bulb or a bullet leaves a gun. Use a transistor amplifier of 1-watt rating or less. (It must have an output transformer) The amplifier is terminated with a resistor on its....
Ul is an op amp used as a comparator. When the test probes are shorted together, resistors R1 and R2 bias the noninverti..
This is a positioning servo drive featuring adjustment of balance, gain, and deadband. In addition to control from a dc signal, mechanical input can be fed into the balance control, or that control could be replaced by a pair of resistance transducers for....
