Vacuum Tubes Valves
Musical & effects
Yagi Uda Antennas
Metal Detector Circuits
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RF & Radiation
Optical Sensing Circuits
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AC to DC & DC to DC
Solar Cell Circuits
Micro Power Circuits
Switching Power Supplies
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Data Bus Circuits
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RF Converter Circuits
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voltage to frequency
Period to Voltage
Video Wall circuits
TV Video Circuits
Motor Control Circuits
8051 / 8052
PCB CAD Software
Car bike Circuits
555 Timer Circuits
Remote Control Toy
H Bridge Circuit
DIY HV Variable Cap
DIY PMA alternator
Interconnection & Timing
Digital Signal Integrity
Digital & Bipolars
Sensors & Detectors
Regulated Power Supply
4 Band Resistor
5 Band resistor
6 Band resistor
Musical & Effects Circuits
Musical & Effects Circuits
The expander to complement the compressor is shown. An external op amp is used for high slew rate. Both the compressor and expander have unity gain levels of 0 dB. Trim networks are shown for distortion (THD) and de shift. The distortion trim should be done first, with an input of 0 dB at 10 kHz. The de shift should be adjusted for minimum...
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 Sl feeds one of those outputs to the 4017B"s reset input.
ICl, a 555 timer, is set up as an astable multivibrator to produce the signal that triggers IC2, a 7490 decade counter. That IC, in turn, produces a BCD output that is fed to IC3, a 7445 BCD-to-decimal decoder/driver. IC3"s output is inverted by two hex inverters, IC4 and IC5. The outputs of IC4 and IC5 are inputted to control pins on IC6 and...
A variable dock-pulse generator is made up of two sections of IC1 (a 4069 CMOS hex inverter). Rl, Sl, and capacitors Cl through C6. By adjusting Rl and switching one of the capacitors into the circuit, the clock"s pulse rate can be varied over a wide range. The TL507C converts analog signals-in this case the output of IC3, an LM386 audio...
A CA3240 dual MOSFET-input device is used as a white-noise source. Op amp IC2 is used as a driver stage for the push-pull output stage formed by Q5 and Q6. Transistors Q2, Q3, and Q4 form a variablefrequency multivibrator. Rll, the speed control, is used to control the multivibrator"s frequency. The output is differentiated by C8 and applied...
Transistors Ql and Q2 form the two halves of a free-running multivibrator whose frequency is determined by the voltage across C8. That capacitor is charged and discharged by closing and openingBwitch Sl. Transistors Q3 and Q4 make up a VFO. The output of the free-running multivibrator frequency modulates the Q3/Q4 oscillator, causing the...
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 frequency, and decreasing the value of Cl decreases the threshold frequency. Transistor Ql is...
A phase shift oscillator using the LM324 operates at an adjustable rate, 5-10 Hz, set by the speed pot. A portion of the oscillator output is taken from the depth pot and used to modulate the on resistance of two 1N914 diodes operating as voltage controlled attenuators.
The tremolo effect is generated by a repeating volume change at a rate usually between 1 and 15Hz. The timer produces a low frequency square wave that is smoothed by a simple rc integrator. This varying signal modulates the signal input from the instrument. Transistor Tl is used as a voltage controlled resistor. The output of the circuit is...
This simple circuit can color the sound coming from your audio system. Clocking for the circuit is provided by an oscillator built from one quarter of a 4093 quad NAND Schmitt trigger. With the component values shown, it will run at about 5 Hz. The clock frequency is fed to the gain control, pin 8, of an LM386 amplifier. Tremolo is...
Often the frequency of a signal must be doubled: modulator/demodulator chip LM1496 is an ideal basis for this. From
In this circuit, Ql is a simple amplifier that has its gain controlled by a variable emitter resistance supplied by FET Q2. In
Analog Delay Line (Echo And Reverb)
This circuit uses an SAD 512D (Reticon) chip, which is a 512-stage analog shift register. By varying th
Musical Envelope Generator And Modulator
A gate voltage is applied to initiate the proceedings. When the gate voltage is in the ON state, Q
This bull horn uses U1 as a driver stage and U2 as an output driver. U1 is set up for a gain of 200. The microphone should have a
Acoustic Sound Receiver
The receiver is an audio amplifier fed by SPKR1, a piezo speaker that is used as a microphone. A scope or headphone
Integrated circuit Ul is connected as a low-frequency asymmetrical oscillator. Its output is inverted by Ql and fed to the reset te
The electronic bagpipe mimics the sound of real instruments. This circuit uses two UJT oscillators and an amplifier (Q3,
10 Note Sound Synthesizer Circuit
As shown, three ICs are used to produce the sounds. ICl is a 555 timer that generates clock pulses. It is configured as an astable multivibrator. The frequency of the clock pulses is set by trim: mer potentiometer PI. These clock pulses are coupled to the input of IC3 (a 4017 CMOS Johnson counter) on its clock input pin 14. Each clock pulse...
Space Age Sound Machine Circuit
The space-age sound device uses a 556 dual-times IC to produce a phasor sound. That IC is actually two 555 timer ICs in one 14-pin package, as shown in the schematic. Each timer inside the 556 is connected iri an astable multivibrator mode. The first timer has its frequency set by Kl, R2, and Cl. Its output appears on pin 5 and it is coupled...
Electronic Gong Circuit
The electronic gong is comprised of an oscillator (built around half of a 74COON quad 2-input NAND gate), an active twin-T filter (built around a TL081), and will drive an audio amplifier IC such as aii LM386N. Pulses from astable multivibrator ICl cause the twin-tee active filter U2 to ring, producing a damped sinusoidal output.
Dual Tone Sounder Circuit
An outside horn-type speaker works best with the circuit. However, such devices require a great deal of power, so this sounder should only be used in alarm circuits where at least a 6-A SCR is used as the sounder driver. A single CMOS 4001 quad 2-input NOR gate, two 2N3904 general- purpose npri transistors, and a single MJE3055 power transistor...
Low Level Sounder Circuit
This is a simple low-level noise maker that`s ideally suited to certain alarm applications. When the sounder is located in another part of the building, the sound level is loud enough to be heard, but is not loud enough to warn off an intruder. A single 2N3904 npn transistor is connected in a Hartley audio oscillator, with a 1 kO to 8-...
Sound Effects Generator Circuit
The circuit consists of four parts: a binary counter, a D/A converter, a VCO, and an audio output amplifier. The speed at which the counter counts depends on the frequency of the output of the VCO, which in turn is determined by the output of the counter. That feedback loop gives this circuit its characteristic output. The initial frequency of...
Extended On Time Timer Circuit
Half of a Motorola MG14538B dual, precision, retriggerable mono stable multivibrator is used to form an extended on-time timer circuit. That type of circuit can be used as a switch debouncer. Such circuits are often used in digital circuitry, where each and every bounce of a switch contact is seen as a separate digital input.
Voltage-controlled amplifier or tremolo circuit
The transistors form a differential pair with an active current-source tail. This configuration, known technically as a variable-transconductance multiplier, has an output proportional to the product of the two input signals. Multiplication occurs due to the dependence of the transistor transconductance on the emitter current bias
Audio Ditherizing Circuit For Digital Audio Use
By adding a small amount of noise to a signal to be digitized (about 0.7 bit): where: n = #
Tone burst generator
The tone burst generator supplies a tone for one-half second after the power supply is activated; its intended use is a communications network alert signal. Cessation of the tone is accomplished at the SCR, which shunts the timing capacitor CI charge current when activated. The SCR is gated on when C2 charges up to the gate voltage which occurs...
The UJT-oscillator frequency is determined by the 100 ÂµÂ¥ capacitor and the effective resistance of the 22 and 470 resistors and the potentiometer. Rate can be varied from 42 to 208 beats/minute.
Twang is a guitar sound that more or less approximates a banjo or mandolin. The circuit produces unusual sounds from an ordinary electric guitar by cutting the bass, severely distorting the midband and highs, and then amplifying the distortion.
Guitar and bass tuner
The heart of the circuit is IC2, a 50240 top-octave generator. That device uses a single input-frequency to generate all twelve notes of the musical scale. The input signal is provided by IC1, a 4001 quad 2-input NOR gate. Two sections of that IC are used to form an oscillator that runs at approximately 2 MHz. The frequency can be adjusted by...
The electronic circuit in the VOX Box consists of three parts: a microphone preamplifier, a Schmitt trigger, and a relay driver. Input signals (MIC INPUT terminals) to the microphone preamplifier (Ul) are amplified and fed to a THRESHOLD control (R8). When the preselected threshold voltage level is exceeded, the output of the Schmitt trigger...
Audio Filters Circuits
Audio Amplifier Circuits
Audio Oscillator Circuits
Audio Mixer Circuits
Audio Equalizer Circuits
Audio Tone Balance Circuits
Beeper Buzzer Circuits
Vacuum-Tube Valves Circuits
Ultrasonic distance finder circuit
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is measured. There are three main categories of distance measurement methods in use: a) By...
Simple Metal detector circuit with CD4030
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to find something potentially valuable, hidden a few centimeters below the soil. So many...
Fully automatic watering circuit for flower pots
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This circuit comes as a solution to this problem. Depending on humidity of the pot at...
Simple deep searching metal detector circuit
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the circuit of this metal detector, it is possible to detect a metal coin in depth of 90 to...
Sub-Harmonic Bass Converter for Electric Guitars
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound, such as filtering or distortion. Instead, a frequency division system produces outputs...
Echo Depth Sounding Sonar for Boats
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the calibration of the rope. This arrangement still exists in some yachts. The big...
100W HiFi Audio Amplifier Circuit
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power supply must be symmetrical so that no electrolytic capacitors are needed at the outlet....
Plant-Pot Water Level Indicator Circuit
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower. The circuit of the device is shown in Figure 2. The water detection is made from the bottom...
Analogue Sound Preasure dB-Meter Circuit
The best human ear can capture sounds from 20Hz to 20KHz. These limits are known to be the broadest that can exist. Normally the normal limits range from 100Hz to about 13KHz and depend on the age and health of the individual. We for our measurements and to have a good accuracy we will get the limits of 20Hz to 20KHz. A sound to be heard does...
DIY HV Variable Capacitor
DIY PMA Alternator Plans
Digital Signal Integrity