New Circuits Page 224
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The NE592 is connected in conjunction with a MC1496 balanced modulator to form an excellent automatic gain control system. The signal is fed to the signal input of the MC1496 and re-coupled to the NE592. Unbalancing the carrier input of the MC1496 causes....
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The LTC®1605 is a new 16-bit, 100ksps ADC from Linear Technology. Its outstanding DC accuracy and ±10V analog input range are ideal for industrial control and instrumentation applications. Its simple I/O, low power and high performance make it easy to design....
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Nice small audio amplifier which use only few parts to give good quality sound. This amp can be used as a simple booster, the heart of a more complicated amplifier or used as a guitar amp. Although not perfect, this amplifier does have a wide frequency....
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This audio amplifier design approach employs TMOS Power FETs operating in a complementary common- source configuration. They are biased to cutoff, then turn on very quickly when a signal is applied. The advantage of this approach is that the output stage is....
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This stereo encoder is the perfect solution for those looking for a high quality stereo sound transmission at a low cost. This stereo encoder produces an excellent crystal clear stereo sound and very good channel separation that can match with many more....
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This converter delivers up to 50 mA from a 6-V battery with 78% efficiency. This flyback converter functions by feedback-controlling the frequency of inductive flyback events. The inductor"s output, rectified and filtered to de, biases the feedback loop to....
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A simple, low component count phase locked loop that locks onto and detects the amplitude of an incoming baseband 7 bit Barker code using a switched resistor demodulator that is driven directly by a microcontroller's output pins. Balanced modulators using....
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The Bray Barometer requires manual calibration for voltage offset and gain. Although practical on the workbench, these devices are most likely mounted in inconvenient locations making secondary adjustment difficult.
The Bray Barometer uses potentiometers....
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The original application for the circuit in Figure 1 was to check the number of revolutions of an engine with only one LED as an indicator. The measurement of the number of revolutions usually involves sensors with a frequency output proportional to the....
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The values of Rl, R2, and D1 are selected for the voltage applied. Using a 12-volt battery, Rl = 10 K, R2 = 5 K and D1 is a 5-volt zener diode, or a string of forward-biased silicon rectifiers equaling about 5 volts. Transistor Ql is a general-purpose UJT....
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This circuit draws very little power, less than 5 mA with a single 6-V power supply. making it ideal for portable battery-operated equipment. The small size and low power consumption belie the 90-dB dynamic range and 10.5-I"V sensitivity. De output voltage....
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The optical signal is coupled to the pin diode. Current flowing in the diode also flows into the input of the NE5211 preamplifier. The preamplifier is a fixed-gain block that has a 28-K!J differential transimpedance and does a single-ended to differential....
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This is a pocket-sized LED flashlight operating with only one AAA battery. However, the super high luminosity LEDs(blue,green or white) require at least 3.5 volts of forward voltage. This flashlight is boosting input voltage up to operating voltage of a LED....
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Maxim/Dallas > Designer`s Library > App Notes > DISPLAY DRIVERS
Keywords: Single FET Controls 2nd LED Array in Switch-Mode LED Backlight
Related Parts
APP 1871: Feb 03, 2003
Download, PDF FormatDownload, PDF Format (29kB)
APPLICATION....
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This generator will supply sine, triangular, and square waves from 2Hz to 20kHz. This complete test instrument can be plugged into a standard 110 Vac line for power. VoVT will be up to ±25 V (50 V pk-pk across loads as small as 10 0 (about 2.5 A maximum....
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Here's something that has always bugged me: light waves are about 5000 Angstroms in wavelength, while atoms are more like 1 Angstrom across. Atoms are thousands of times smaller than light waves, yet atoms obviously interact very strongly with light. How can....
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Most portable systems have built-in PCMCIA sockets as
the sole means of expansion. The requirements of the
PCMCIA specification have led to some confusion among
system designers. This Design Note will attempt to lessen
the confusion and highlight other....
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This circuit was designed to make switching of a 48-channel mobile transceiver safe to operate while mobile. The oscillators allow for single-stepping or a scanning function. The scan facility allows for stepping through all 48 channels to check for....
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This is an op-amp implementation of a Vox style wah, with the inductor replaced by a gyrator circuit. With the component values given the frequency response is similar to a standard wah. By replacing one of the resistors with a potentiometer the simulated....
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This is a lamp timer capable of operating two separate relay switches. Outputs can be in three (or restricted to two) states: OFF, delayed ON and constant ON. Delayed ON mode is indicated by the LEDs. The source code is easily customizable for your needs:....
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This circuit mimics the dual-tone drone sound that"s produced by the unusual wind instrument. Urnjunction transistors Ql and Q2 are connected in similar audio-oscillator circuits. Each of the oscillator frequencies is determined by one of the two resistors....
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This circuit will allow a multimeter to display the positive or negative peaks of an incoming signal. A 741, JC1, is used in the noninverting mode with R1 defining the input impedance. D1 or D2 will conduct on a positive or negative peak, charging C2 until....
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This simple receiver AF amplifier can supply several hundred milliwatts to an 8- speaker. The gain is about 200X. If..
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A simple means of generating a low-power voltage supply of opposite polarity from the main supply. Self oscillating driver produces pulses at a repetition frequency of 100 kHz. When the VMOS device is off, capacitor C is charged to the positive supply. When....
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Regulation is provided by taking the rectified output of the sense winding and applying it as a bias to the base of Q2 via zener Dl. The collector of Q2 then removes drive from the gate of Ql. Therefore, if the . output voltage should increase, Q2 removes....
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CallID Unit based on Motorola MC68HC11A1P & MC145447P chips compatible with the standard protocols. if you got a multimeter and a phone you can start testing. Check the voltage across the pair, should be 48VDC in US, 60VDC in Europe. Place a 600 ohm....
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This supply generates an initial high voltage for ignition purposes. After ignition, the supply generates about 1300 to 1500 V. If a higher ignition voltage (than the 6000 V supplied) is necessary,..
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This circuit reconstructs and separates analog signals which have been time-division multiplexed. The conventional method, shown on the left, has several restrictions, particularly when a short dwell time and a long, accurate hold time is required. The....
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In this circuit, oscillator Ql runs at about 15 kHz and feeds mixer Ul. Ul has an internal oscillator that runs a..
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L1 is 0.112uH (this tunes to the middle of the FM band, 98 MHz, with VC1 at its centre value of 33pF). L1 is 5 turns of 22 swg enamelled copper wire close-wound on a 5mm (3/16") diameter former. Alternatively, you can have a fixed 33pF cap instead of VC1 and....
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ICla and IClb form an astable multivibrator. The astable"s signal is fed to IC1c, also to the clock input of IC2, a 4017B decade counter. That IC"s QO through Q9 outputs become high one at a time for each successive clock pulse received at1Jin 14. Switch....
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The TiltStick is a small acceleration sensing device in form of a USB stick. It's using a two axis acceleration sensor to measure acceleration (caused e.g. by motion and tilt). The device is emulating a USB joystick and can thus be used in conjunction with....
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A timer (LM555CN) and decode counter is used to generate duty cycles from 10% to 100% to control the time a heating system can operate. V2 is a decode counter that can be switched from 10% to 100% duty cycle. V3A and form a latch that drive Al, LED1, and....
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The circuit in Figure 1 meets these criteria and uses only three off-the-shelf ICs and a few passive components. Although dedicated to conditioning the low-level signal a strain-gauge bridge produces, the circuit can operate with almost any resistive....
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An eight watt amplifier based on the LM383 power audio amplifier ic. It`s advised that you use this ic with a suitable heatsink...
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The circuit presented is experimental, and should provide some fun to build and play about with. It has been built and tested, and works very well indeed. Please note that it is a low current Class-A opamp, and is incapable of driving low impedances. The....
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With graphic equalizer we make selective cutting off or boost, of selected departments of acoustic spectrum. With this way we can adapt the musical reproduction, in the characteristics of space where we hear. This can create however also problems if go to....
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This circuit is useful for removing ground loop hum on a remote line level audio signal line. It can be used to to connect a computer sound card to a stereo amplifier`s line input. Other uses include tapping into a line level signal for powering a remote....
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The waveforms in Figure 1 illustrate good and bad power-factor conditions. Trace A, at the top of the figure, is the voltage common to the current waveforms below. Trace B is an ideal current, in phase, with a 1.0 power factor and delivering peak current of....
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This circuit will supply up to about 20ma at 12 volts. It uses capacitive reactance instead of resistance; and it doesn`t generate very much heat.The circuit draws about 30ma AC. Always use a fuse and/or a fusible resistor to be on the safe side. The values....
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A16 V power supply can be synthesized as shown using IN1692 rectifiers. A shift pulse input saturates the 2N2714 depriving the Darlington combination (2N2714 and 2N2868) of base drive..
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This circuit needs a a Faraday shield, which is connected to 0V.To make this one wrap a tin foil around the coil.and connect to 0v.Then you can use this circuit for find metal.Tune your mw radio until whistle sound comes...
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Here is a diagram of the internals of the MAX232A. It shows a double charge pump voltage doubler and a +10v to -10v voltage inverter. The voltages output are used to generate the RS-232 compliant signals. The MAX232A has provisions for two serial ports on....
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The 555 acts as the tone generator configured in the astable mode. Its pin 3. square-wave output is transformed into a triangle wave by Rl and C2. The voice"s pitch is controlled by RL Transistor Ql can be 2N1086, 2N1091, or any other equivalent npn....
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Laser-receiver circuits must bias their avalanche photo diodes (APD) to achieve optimal gain. Unfortunately, an APD..
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Ql is a fixed oscillator operating at 455 kHz. Ul is a mixer, with its own internal oscillator running at 45..
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Q1 and Q2 form a differential stage which single- ends into the LT1010. The capacitively terminated feedback divider gives the circuit a de gain of 1, while allowing ac gains up to 10. Using a 20-fl bias resistor, the circuit delivers 1 V pk-pk into a....
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This circuit uses a tachometer to generate a feedback signal which is compared to a reference supplied by the auxiliary output. When power is applied, the tachometer output is zero and the regulator output comes on, forcing current into the motor. As....
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# The circuit can produce about 250-500mA at 2KV, depending on the transformer.
# For C1, you can use the capacitor out of an old microwave.
# This circuit is mainly provided as a demonstration of using commonly available parts for something uncommon.....
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A basic mains driven Cockroft ladder high voltage generator is shown in the schematic. This is functionally the same as a project in Electronics Today International many years ago. The peak mains voltage of 340V appears across each capacitor and this is....
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A circuit that will find enough applications. Basically the designing became in order to exist delay in quench one or more lamps in a stairwell or in any other space exists this need. It can become use, for the control various motor or other appliances, what....
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These photos were made in the years 1956 and 1957. On photo nr. 3, on the right, at the bottom, is the GMD. The work that was done at the objekt was of course top secret. It was strictly forbidden to talk to any acquaintance or relative about the work.....
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This complete high quality, low noise mono audio power amplifier is based around the Hybrid Integrated Circuit STK4050 manufactured by Sanyo. The circuit incorporates volume and has a maximum music output power of 200W.The circuit incorporates an on board....
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This project is an experiment of the Digital Signal Processing with a cheap microcontroller instead of an ordinary digital signal processor. Recent 8 bit microcontrollers have sufficient processing performance so that they can be used for simple audio signal....
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The circuit will produce the current relationship to within 2% using 1% values for Rl through R5. This includes variations in Rl from 100 ohm to 2000 ohm. The use of large resistors for Rl through R4 minimizes the error due to Rl variations..
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This simple circuit generates narrow pulses at about 700-800Hz frequency. The pulses, containing harmonics up to the MHz region, can be injected into audio or radio-frequency stages of amplifiers, receivers and the like for testing purposes. A high-pitched....
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Light-emitting diodes connected with reverse polarity provide a visual indication of zero-beat frequency. Each LED is on for only half a cycle of the input. When the input frequency is more than 1 kilohertz away from the zero-beat frequency, both LEDs appear....
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This may well be the world`s only discreet logic circuit to generate truely random output. It makes an excellent candle flicker light for your haloween pumpkin, and looks much more authentic than a shimmer light wherever a good a simulated flame effect is....
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The clock circuit above uses seven ICs and 19 LEDs to indicate binary coded decimal time. The LEDs can be arranged (as shown in example above) so that each horizontal group of 3 or 4 LEDs represents a decimal digit between 0 and 9 and each individual LED....
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The transmitter is shown and although straightforward, there are a couple of tricks that I had to incorporate to minimise battery drain during standby. Although the PIC quiescent current is only 200uA, that will still flatten a pair of AA or AAA 1.5V cells....
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An oscillator, a small power stage, some modulation, and a tiny loop antenna make RF for experiments on at 187.5 kHz on the United States' FCC Part 15 Lowfer band (1600-1750 meters). This is a low power signal source I put together one evening to provide....
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You may find that there are too few, if your power is very noisy (as can happen in a car environment) it may help to place a 0.1uF and/or 10uF capacitor before and/or after the voltage regulator. At the moment I`m not using these but at this point I`ve only....
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This solid-state switch senses and interrupts an overcurrent condition within 2 /is. II allows the circuit to float. IC..
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These photoflash, or strobe, capacitors range in value from a hundred microfarads to over a millifarad, with target output voltages above 300V. Traditional strobe capacitor charging methods are either inefficient or require software overhead. The LT3420....
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This circuit uses only one IC, produces a pleasant tone, and sports a single control for adjusting the tone"s chiming rat..
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This temperature controller operates as a pulse snatching device, which allows it to run at its own speed and tum on at the zero crossing of the line frequency. Zero crossing tum-on reduces the generation of line noise transients. TMOS Power FET, Ql, is....
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The alarm/sensor circuit shown is built around two SCRs, a transistor, a 4049 hex inverter, and a few support components, all of which combine to form a closed-loop detection circuit with a delay feature. The delay feature allows you to enter a protected....
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With the circuit shown here the response at one octave off tune is within 10% of the far out response: notch sharpness may be increased or reduced by reducing or increasing.respectively the 68 ohm resistor. Linearity tracking of R8 and R9 has no effect on....
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The circuit is built around a 555 oscillator/ timer. The circuit provides two time periods. The long-running time period is adjustable from about 1 to 10 minutes, and the short time period is preset to about three seconds. Here`s how the dual timer....
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This design for a headphone amplifier arose after the purchase of commercial equipment with separate pre and power amplifiers without a headphone output. Its advantages are ...
* low output impedance to drive several pairs of phones
* the active....
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this circuit uses the LM3914 and should be powered by its own battery, otherwise you might get an innacurate reading. hook the to-be-monitored battery to pin 5 of the chip...
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The special feature of the circuit shown below is the low consumption. With voltage n 9 at the entrance and no exit load, absorbs current 50 ma, which is certainly very small compared with a quiescent current 78L05. The components that comprise it are....
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This Project Digital Calendar using Microcontroller is an advanced digital calendar, which displays the Date, Day, Month over the LED display. It has an 8 bit Microcontroller which runs on the Program embedded on its ROM. Separate LEDs are provided for the....
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You usually use PC hardware monitors to keep a close eye on power-supply voltage levels, the speed of system cooling fans, and even the temperature of the CPU. Until fairly recently, this level of system monitoring was reserved for high-end servers running....
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A while ago I got an email asking for the schematic of a circuit to detect cut phone lines. It didn`t take me long to find this circuit in Electronics Now. When the circuit detects that a phone line has been cut, it activates a MOSFET which can be used to....
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Transistor Ql of the headset amplifier circuit amplifies the 30 mV signal, that would have gone to the earphones, to .5 V. which sufficiently drives the stereo earphones. Capacitor Cl blocks any de current from shorting back into the telephone base.....
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My FM Wireless Microphone has been a very popular project with beginners and experienced constructors alike. It has been used inside guitars and as the basis of a remote control system. I do however, receive many requests for a higher powered circuit and....
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This project is offered totally Free for those who are interested in it.
I have tried to make this article as complete as possible, but I will Not
assume any lilability for any "Errors or Omissions" in this article.
If Needed, I will attempt to help you....
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This battery-powered metal detector uses four exclusive-OR gates contained in the 4030 CMOS integrated circuit. The gates are wired as a twin-oscillators and a search coil serves as the inductance element in one of the oscillators. When the coil is brought....
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A tiny sandwich flag connected perpendicular to the motor spindle aids observation of how long it takes to complete one full rotation. This worked initially, as each burst from the capacitor barely moved the flag 1/4 of a rotation. As the circuit variations....
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This is a new circuit I just finished. I like the white LED lighting, it is softer and give a better view without being overly bright for the eyes when you just wake up in the middle of the night. This circuit has no transformer to isolate it, so it is a....
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Soundblaster soundcard series (SB16, SB32, AWE32 and AWE64) have all a microphone input designed to be used with the electret microphones which come with the soundcard package (some packages) or with separate microphone designed to be used with SoundBlaster....
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The beat rate may be determined by operating a foot pedal in much the same manner as for a real drum, or by means of an internal oscillator, the speed of which may be preset.
..
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The VCO of Ul, a phased-locked loop. produces a low-frequency square-wave signal from 5 Hz to 2500Hz, which is controlled by varying the voltage to pin 9 via R2. The frequency threshold is set by Rl and Cl. Increasing the value of Rl increases the....
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This universal filter offers low-pass, high-pass, bandpass, band elimination, and all-pass functions. The Biquad consists of two successive integration stages followed by an inverting stage. The entire group has a feedback loop from the front to the....
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In operation. the alarm circuit allows a 0-47 second time delay, as determined by the Rl/Cl combination, after the switch is armed to allow the vehicle"s motion sensor to settle down. This allows you time to get a bag of groceries out of the trunk and not....
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This circuit is designed to be used in conjunction with the standard 4 foot square loop used in MW for long distance reception...
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Active loudspeakers have a lot of advantages concerning simple loudspeakers that use passive components for the elements concretisation of segregation of frequencies. In the case of active loudspeakers we have, proportionally, bigger build cost, because each....
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The circuit is based around {LM4702}manufactured by NATIONAL semiconductors&{MJ11029-MJ11028} by ON semiconductors It is a high fidelity audio power amplifier. Designed for demanding consumer and pro-audio applications. You can also use this circuit with AV....
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The ground side of the speaker is connected to the junction of two equal high value capacitors (1000 µf is typical) across the supply. The amplifier output voltage will be Vs/2, and so will the voltage across CI (if CI and C2 are equal); so as the supply....
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The preamp featured is very straightforward to make on the PCB, and has an innovative tone defeat function. Rather than completely disable the tone controls, they are massively de-sensitised, and when "defeated" have a maximum range as shown in Fig. 3....
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Only one LED can be on when the circuit is at rest. Which LED is illuminated is determined by the touch pick-up that last had human contact. Pickup terminal A controls the on condition of LEDl, and terminal B controls the on condition of LED2. ..
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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`s simple, reliable, "rugged" and short-proof, featuring variable voltage up to 24V and variable current....
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PC parallel port can be very useful I/O channel for connecting your own circuits to PC. The PC`s parallel port can be used to perform some very amusing hardware interfacing experiments. The port is very easy to use when you first understand some basic....
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This circuit modulates the current through a lamp filament. Use a low-voltage lamp with a thin, straight filament. They h..
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A very simple LED flasher circuit. With HT-2014L the circuit produces 1 flash per second and the HT-2014M produces 2 flashes per second...
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Hand held computers are rapidly moving to 3V logic to save
power. Yet higher voltage buses are still utilized elsewhere in
the system for display driving and other functions. The
LT1330 is functionally equivalent to the LT1237 but operates
from 5V with a....
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A basic circuit to trigger an SCR is shown in Fig. 67 -lA. This circuit has the disadvantage that the blocking voltage of the photon-coupler output device determines the circuit-blocking voltage, irrespective of higher main SCR capability. Adding....
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The current out is Iqut—Vin/R. For negative currents, a PNP can be used and, for better accuracy,-a Darlington pair can be substituted for the transistor. With careful design, this circuit can be used to control currents of many amps..
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The switching power supply, shown in the schematic, provides 12 volts, at 10 amps, maximum, using a discrete transistor regulator with an op-amp functioning as a comparator in the feedback circuit. The supply was constructed in 1984 and is variable....
The NE592 is connected in conjunction with a MC1496 balanced modulator to form an excellent automatic gain control system. The signal is fed to the signal input of the MC1496 and re-coupled to the NE592. Unbalancing the carrier input of the MC1496 causes....
The LTC®1605 is a new 16-bit, 100ksps ADC from Linear Technology. Its outstanding DC accuracy and ±10V analog input range are ideal for industrial control and instrumentation applications. Its simple I/O, low power and high performance make it easy to design....
Nice small audio amplifier which use only few parts to give good quality sound. This amp can be used as a simple booster, the heart of a more complicated amplifier or used as a guitar amp. Although not perfect, this amplifier does have a wide frequency....
This audio amplifier design approach employs TMOS Power FETs operating in a complementary common- source configuration. They are biased to cutoff, then turn on very quickly when a signal is applied. The advantage of this approach is that the output stage is....
This stereo encoder is the perfect solution for those looking for a high quality stereo sound transmission at a low cost. This stereo encoder produces an excellent crystal clear stereo sound and very good channel separation that can match with many more....
This converter delivers up to 50 mA from a 6-V battery with 78% efficiency. This flyback converter functions by feedback-controlling the frequency of inductive flyback events. The inductor"s output, rectified and filtered to de, biases the feedback loop to....
A simple, low component count phase locked loop that locks onto and detects the amplitude of an incoming baseband 7 bit Barker code using a switched resistor demodulator that is driven directly by a microcontroller's output pins. Balanced modulators using....
The Bray Barometer requires manual calibration for voltage offset and gain. Although practical on the workbench, these devices are most likely mounted in inconvenient locations making secondary adjustment difficult. The Bray Barometer uses potentiometers....
The values of Rl, R2, and D1 are selected for the voltage applied. Using a 12-volt battery, Rl = 10 K, R2 = 5 K and D1 is a 5-volt zener diode, or a string of forward-biased silicon rectifiers equaling about 5 volts. Transistor Ql is a general-purpose UJT....
This circuit draws very little power, less than 5 mA with a single 6-V power supply. making it ideal for portable battery-operated equipment. The small size and low power consumption belie the 90-dB dynamic range and 10.5-I"V sensitivity. De output voltage....
The optical signal is coupled to the pin diode. Current flowing in the diode also flows into the input of the NE5211 preamplifier. The preamplifier is a fixed-gain block that has a 28-K!J differential transimpedance and does a single-ended to differential....
This is a pocket-sized LED flashlight operating with only one AAA battery. However, the super high luminosity LEDs(blue,green or white) require at least 3.5 volts of forward voltage. This flashlight is boosting input voltage up to operating voltage of a LED....
This generator will supply sine, triangular, and square waves from 2Hz to 20kHz. This complete test instrument can be plugged into a standard 110 Vac line for power. VoVT will be up to ±25 V (50 V pk-pk across loads as small as 10 0 (about 2.5 A maximum....
Here's something that has always bugged me: light waves are about 5000 Angstroms in wavelength, while atoms are more like 1 Angstrom across. Atoms are thousands of times smaller than light waves, yet atoms obviously interact very strongly with light. How can....
This circuit was designed to make switching of a 48-channel mobile transceiver safe to operate while mobile. The oscillators allow for single-stepping or a scanning function. The scan facility allows for stepping through all 48 channels to check for....
This is an op-amp implementation of a Vox style wah, with the inductor replaced by a gyrator circuit. With the component values given the frequency response is similar to a standard wah. By replacing one of the resistors with a potentiometer the simulated....
This is a lamp timer capable of operating two separate relay switches. Outputs can be in three (or restricted to two) states: OFF, delayed ON and constant ON. Delayed ON mode is indicated by the LEDs. The source code is easily customizable for your needs:....
This circuit mimics the dual-tone drone sound that"s produced by the unusual wind instrument. Urnjunction transistors Ql and Q2 are connected in similar audio-oscillator circuits. Each of the oscillator frequencies is determined by one of the two resistors....
This circuit will allow a multimeter to display the positive or negative peaks of an incoming signal. A 741, JC1, is used in the noninverting mode with R1 defining the input impedance. D1 or D2 will conduct on a positive or negative peak, charging C2 until....
This simple receiver AF amplifier can supply several hundred milliwatts to an 8- speaker. The gain is about 200X. If..
A simple means of generating a low-power voltage supply of opposite polarity from the main supply. Self oscillating driver produces pulses at a repetition frequency of 100 kHz. When the VMOS device is off, capacitor C is charged to the positive supply. When....
Regulation is provided by taking the rectified output of the sense winding and applying it as a bias to the base of Q2 via zener Dl. The collector of Q2 then removes drive from the gate of Ql. Therefore, if the . output voltage should increase, Q2 removes....
This supply generates an initial high voltage for ignition purposes. After ignition, the supply generates about 1300 to 1500 V. If a higher ignition voltage (than the 6000 V supplied) is necessary,..
This circuit reconstructs and separates analog signals which have been time-division multiplexed. The conventional method, shown on the left, has several restrictions, particularly when a short dwell time and a long, accurate hold time is required. The....
In this circuit, oscillator Ql runs at about 15 kHz and feeds mixer Ul. Ul has an internal oscillator that runs a..
L1 is 0.112uH (this tunes to the middle of the FM band, 98 MHz, with VC1 at its centre value of 33pF). L1 is 5 turns of 22 swg enamelled copper wire close-wound on a 5mm (3/16") diameter former. Alternatively, you can have a fixed 33pF cap instead of VC1 and....
ICla and IClb form an astable multivibrator. The astable"s signal is fed to IC1c, also to the clock input of IC2, a 4017B decade counter. That IC"s QO through Q9 outputs become high one at a time for each successive clock pulse received at1Jin 14. Switch....
The TiltStick is a small acceleration sensing device in form of a USB stick. It's using a two axis acceleration sensor to measure acceleration (caused e.g. by motion and tilt). The device is emulating a USB joystick and can thus be used in conjunction with....
A timer (LM555CN) and decode counter is used to generate duty cycles from 10% to 100% to control the time a heating system can operate. V2 is a decode counter that can be switched from 10% to 100% duty cycle. V3A and form a latch that drive Al, LED1, and....
The circuit in Figure 1 meets these criteria and uses only three off-the-shelf ICs and a few passive components. Although dedicated to conditioning the low-level signal a strain-gauge bridge produces, the circuit can operate with almost any resistive....
An eight watt amplifier based on the LM383 power audio amplifier ic. It`s advised that you use this ic with a suitable heatsink...
The circuit presented is experimental, and should provide some fun to build and play about with. It has been built and tested, and works very well indeed. Please note that it is a low current Class-A opamp, and is incapable of driving low impedances. The....
With graphic equalizer we make selective cutting off or boost, of selected departments of acoustic spectrum. With this way we can adapt the musical reproduction, in the characteristics of space where we hear. This can create however also problems if go to....
This circuit is useful for removing ground loop hum on a remote line level audio signal line. It can be used to to connect a computer sound card to a stereo amplifier`s line input. Other uses include tapping into a line level signal for powering a remote....
This circuit will supply up to about 20ma at 12 volts. It uses capacitive reactance instead of resistance; and it doesn`t generate very much heat.The circuit draws about 30ma AC. Always use a fuse and/or a fusible resistor to be on the safe side. The values....
A16 V power supply can be synthesized as shown using IN1692 rectifiers. A shift pulse input saturates the 2N2714 depriving the Darlington combination (2N2714 and 2N2868) of base drive..
This circuit needs a a Faraday shield, which is connected to 0V.To make this one wrap a tin foil around the coil.and connect to 0v.Then you can use this circuit for find metal.Tune your mw radio until whistle sound comes...
Here is a diagram of the internals of the MAX232A. It shows a double charge pump voltage doubler and a +10v to -10v voltage inverter. The voltages output are used to generate the RS-232 compliant signals. The MAX232A has provisions for two serial ports on....
The 555 acts as the tone generator configured in the astable mode. Its pin 3. square-wave output is transformed into a triangle wave by Rl and C2. The voice"s pitch is controlled by RL Transistor Ql can be 2N1086, 2N1091, or any other equivalent npn....
Laser-receiver circuits must bias their avalanche photo diodes (APD) to achieve optimal gain. Unfortunately, an APD..
Ql is a fixed oscillator operating at 455 kHz. Ul is a mixer, with its own internal oscillator running at 45..
Q1 and Q2 form a differential stage which single- ends into the LT1010. The capacitively terminated feedback divider gives the circuit a de gain of 1, while allowing ac gains up to 10. Using a 20-fl bias resistor, the circuit delivers 1 V pk-pk into a....
This circuit uses a tachometer to generate a feedback signal which is compared to a reference supplied by the auxiliary output. When power is applied, the tachometer output is zero and the regulator output comes on, forcing current into the motor. As....
# The circuit can produce about 250-500mA at 2KV, depending on the transformer. # For C1, you can use the capacitor out of an old microwave. # This circuit is mainly provided as a demonstration of using commonly available parts for something uncommon.....
A basic mains driven Cockroft ladder high voltage generator is shown in the schematic. This is functionally the same as a project in Electronics Today International many years ago. The peak mains voltage of 340V appears across each capacitor and this is....
A circuit that will find enough applications. Basically the designing became in order to exist delay in quench one or more lamps in a stairwell or in any other space exists this need. It can become use, for the control various motor or other appliances, what....
These photos were made in the years 1956 and 1957. On photo nr. 3, on the right, at the bottom, is the GMD. The work that was done at the objekt was of course top secret. It was strictly forbidden to talk to any acquaintance or relative about the work.....
This complete high quality, low noise mono audio power amplifier is based around the Hybrid Integrated Circuit STK4050 manufactured by Sanyo. The circuit incorporates volume and has a maximum music output power of 200W.The circuit incorporates an on board....
This project is an experiment of the Digital Signal Processing with a cheap microcontroller instead of an ordinary digital signal processor. Recent 8 bit microcontrollers have sufficient processing performance so that they can be used for simple audio signal....
The circuit will produce the current relationship to within 2% using 1% values for Rl through R5. This includes variations in Rl from 100 ohm to 2000 ohm. The use of large resistors for Rl through R4 minimizes the error due to Rl variations..
This simple circuit generates narrow pulses at about 700-800Hz frequency. The pulses, containing harmonics up to the MHz region, can be injected into audio or radio-frequency stages of amplifiers, receivers and the like for testing purposes. A high-pitched....
Light-emitting diodes connected with reverse polarity provide a visual indication of zero-beat frequency. Each LED is on for only half a cycle of the input. When the input frequency is more than 1 kilohertz away from the zero-beat frequency, both LEDs appear....
This may well be the world`s only discreet logic circuit to generate truely random output. It makes an excellent candle flicker light for your haloween pumpkin, and looks much more authentic than a shimmer light wherever a good a simulated flame effect is....
The clock circuit above uses seven ICs and 19 LEDs to indicate binary coded decimal time. The LEDs can be arranged (as shown in example above) so that each horizontal group of 3 or 4 LEDs represents a decimal digit between 0 and 9 and each individual LED....
The transmitter is shown and although straightforward, there are a couple of tricks that I had to incorporate to minimise battery drain during standby. Although the PIC quiescent current is only 200uA, that will still flatten a pair of AA or AAA 1.5V cells....
An oscillator, a small power stage, some modulation, and a tiny loop antenna make RF for experiments on at 187.5 kHz on the United States' FCC Part 15 Lowfer band (1600-1750 meters). This is a low power signal source I put together one evening to provide....
You may find that there are too few, if your power is very noisy (as can happen in a car environment) it may help to place a 0.1uF and/or 10uF capacitor before and/or after the voltage regulator. At the moment I`m not using these but at this point I`ve only....
This solid-state switch senses and interrupts an overcurrent condition within 2 /is. II allows the circuit to float. IC..
This circuit uses only one IC, produces a pleasant tone, and sports a single control for adjusting the tone"s chiming rat..
This temperature controller operates as a pulse snatching device, which allows it to run at its own speed and tum on at the zero crossing of the line frequency. Zero crossing tum-on reduces the generation of line noise transients. TMOS Power FET, Ql, is....
The alarm/sensor circuit shown is built around two SCRs, a transistor, a 4049 hex inverter, and a few support components, all of which combine to form a closed-loop detection circuit with a delay feature. The delay feature allows you to enter a protected....
With the circuit shown here the response at one octave off tune is within 10% of the far out response: notch sharpness may be increased or reduced by reducing or increasing.respectively the 68 ohm resistor. Linearity tracking of R8 and R9 has no effect on....
The circuit is built around a 555 oscillator/ timer. The circuit provides two time periods. The long-running time period is adjustable from about 1 to 10 minutes, and the short time period is preset to about three seconds. Here`s how the dual timer....
This design for a headphone amplifier arose after the purchase of commercial equipment with separate pre and power amplifiers without a headphone output. Its advantages are ... * low output impedance to drive several pairs of phones * the active....
this circuit uses the LM3914 and should be powered by its own battery, otherwise you might get an innacurate reading. hook the to-be-monitored battery to pin 5 of the chip...
The special feature of the circuit shown below is the low consumption. With voltage n 9 at the entrance and no exit load, absorbs current 50 ma, which is certainly very small compared with a quiescent current 78L05. The components that comprise it are....
This Project Digital Calendar using Microcontroller is an advanced digital calendar, which displays the Date, Day, Month over the LED display. It has an 8 bit Microcontroller which runs on the Program embedded on its ROM. Separate LEDs are provided for the....
A while ago I got an email asking for the schematic of a circuit to detect cut phone lines. It didn`t take me long to find this circuit in Electronics Now. When the circuit detects that a phone line has been cut, it activates a MOSFET which can be used to....
Transistor Ql of the headset amplifier circuit amplifies the 30 mV signal, that would have gone to the earphones, to .5 V. which sufficiently drives the stereo earphones. Capacitor Cl blocks any de current from shorting back into the telephone base.....
My FM Wireless Microphone has been a very popular project with beginners and experienced constructors alike. It has been used inside guitars and as the basis of a remote control system. I do however, receive many requests for a higher powered circuit and....
This project is offered totally Free for those who are interested in it. I have tried to make this article as complete as possible, but I will Not assume any lilability for any "Errors or Omissions" in this article. If Needed, I will attempt to help you....
This battery-powered metal detector uses four exclusive-OR gates contained in the 4030 CMOS integrated circuit. The gates are wired as a twin-oscillators and a search coil serves as the inductance element in one of the oscillators. When the coil is brought....
A tiny sandwich flag connected perpendicular to the motor spindle aids observation of how long it takes to complete one full rotation. This worked initially, as each burst from the capacitor barely moved the flag 1/4 of a rotation. As the circuit variations....
This is a new circuit I just finished. I like the white LED lighting, it is softer and give a better view without being overly bright for the eyes when you just wake up in the middle of the night. This circuit has no transformer to isolate it, so it is a....
Soundblaster soundcard series (SB16, SB32, AWE32 and AWE64) have all a microphone input designed to be used with the electret microphones which come with the soundcard package (some packages) or with separate microphone designed to be used with SoundBlaster....
The beat rate may be determined by operating a foot pedal in much the same manner as for a real drum, or by means of an internal oscillator, the speed of which may be preset. ..
The VCO of Ul, a phased-locked loop. produces a low-frequency square-wave signal from 5 Hz to 2500Hz, which is controlled by varying the voltage to pin 9 via R2. The frequency threshold is set by Rl and Cl. Increasing the value of Rl increases the....
This universal filter offers low-pass, high-pass, bandpass, band elimination, and all-pass functions. The Biquad consists of two successive integration stages followed by an inverting stage. The entire group has a feedback loop from the front to the....
In operation. the alarm circuit allows a 0-47 second time delay, as determined by the Rl/Cl combination, after the switch is armed to allow the vehicle"s motion sensor to settle down. This allows you time to get a bag of groceries out of the trunk and not....
This circuit is designed to be used in conjunction with the standard 4 foot square loop used in MW for long distance reception...
Active loudspeakers have a lot of advantages concerning simple loudspeakers that use passive components for the elements concretisation of segregation of frequencies. In the case of active loudspeakers we have, proportionally, bigger build cost, because each....
The circuit is based around {LM4702}manufactured by NATIONAL semiconductors&{MJ11029-MJ11028} by ON semiconductors It is a high fidelity audio power amplifier. Designed for demanding consumer and pro-audio applications. You can also use this circuit with AV....
The ground side of the speaker is connected to the junction of two equal high value capacitors (1000 µf is typical) across the supply. The amplifier output voltage will be Vs/2, and so will the voltage across CI (if CI and C2 are equal); so as the supply....
The preamp featured is very straightforward to make on the PCB, and has an innovative tone defeat function. Rather than completely disable the tone controls, they are massively de-sensitised, and when "defeated" have a maximum range as shown in Fig. 3....
Only one LED can be on when the circuit is at rest. Which LED is illuminated is determined by the touch pick-up that last had human contact. Pickup terminal A controls the on condition of LEDl, and terminal B controls the on condition of LED2. ..
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`s simple, reliable, "rugged" and short-proof, featuring variable voltage up to 24V and variable current....
PC parallel port can be very useful I/O channel for connecting your own circuits to PC. The PC`s parallel port can be used to perform some very amusing hardware interfacing experiments. The port is very easy to use when you first understand some basic....
This circuit modulates the current through a lamp filament. Use a low-voltage lamp with a thin, straight filament. They h..
A very simple LED flasher circuit. With HT-2014L the circuit produces 1 flash per second and the HT-2014M produces 2 flashes per second...
A basic circuit to trigger an SCR is shown in Fig. 67 -lA. This circuit has the disadvantage that the blocking voltage of the photon-coupler output device determines the circuit-blocking voltage, irrespective of higher main SCR capability. Adding....
The current out is Iqut—Vin/R. For negative currents, a PNP can be used and, for better accuracy,-a Darlington pair can be substituted for the transistor. With careful design, this circuit can be used to control currents of many amps..
The switching power supply, shown in the schematic, provides 12 volts, at 10 amps, maximum, using a discrete transistor regulator with an op-amp functioning as a comparator in the feedback circuit. The supply was constructed in 1984 and is variable....
