This circuit enables observation of movement between other stroboscopes. Generation of rectangular signal is based on NE555. This circuit requires a low power supply that is made from a simple transformer TR1, traditional rectifier bridge and zener diode.....

This is a useful instrument for works hops. The standard of the produced frequencies is 10 to 1. The basic frequency is produced by a crystal with high accuracy. The circuit is consisted by the oscillator, around the crystal and the frequency divider, which....

The circuit works from a symmetrical 40 VDC power supply and draws a maximum current of 2.6 A. The input circuit of the amplifier is a differential amplifier built around Q4 and Q5 that employ DC feedback thus preventing any DC voltage from appearing....

The above diagram is a standard low-pass telephone line filter (L1,C1,L3,C2). L2 and L4 are needed since we're dealing with the 'Tip' and 'Ring' of a phone line which may carry up to 90VAC. I used a similar circuit on 3 phone-lines back in the early 80's....

This little circuit can be used to dim lights up to about 350 watts. It uses a simple, standard TRIAC circuit that, in my expirience, generates very little heat. Please note that this circuit cannot be used with fluorescent lights...

In order to simplify the transmitter design, we've used the new pll circuit from Motorola :the MC145170. This PLL includes the prescaler and a serial standard bus called SPI. We advise to use the P2 version that fixes some init issues during the Power Up.....

When the start switch is pushed, the output of the charger goes to 14.5 V. As the batttery approaches full charge, the charging current decreases and the output voltage is reduced form 14.5V to about 12.5V, terminating the charging process. Transistor Q1....

Many things can go wrong in a modern recording studio, but few are as difficult to track down as reversed microphone polarity. When a microphone is placed in front of a sound source, a positive pressure on its diaphragm caused by forward-moving air results....

This Design Idea describes a versatile test circuit for zener diodes after yet another misread zener diode had infiltrated the ranks of 1N4148 diodes assembled on a pc board. As a bonus, the circuit can serve as a moderate-voltage, power-limited adjustable....

This circuit is mainly intended to provide common home stereo amplifiers with a microphone input. This circuit is mainly intended to provide common home stereo amplifiers with a microphone input. Using a stereo microphone the circuit must be doubled. In....

The circuit is a microphone amplifier for use with low impedance (~200 ohm) microphones. It will work with stabilized voltages between 6-30VDC. If you don`t build the impedance adapter part with T1, you get a micamp for higher impedance microphones. In this....

The circuit in Figure 1 uses a Centronics printer port to interface an eight-channel, 8-bit ADC to a PC. The circuit cuts the cost of addressing and decoder circuitry and saves one expansion slot for interfacing. The design uses three of the subport`s....

This preamplifier has a low output impedance, and is designed to drive long cables, allowing you to listen to a remote music source without having to buy expensive screened cables. The very low output impedance of around 16 ohms at 1KHz, makes it possible to....

Here is a simple radio that is easy to build and inexpensive. In fact, you probobly have all the parts you need in your junk box. You`ll be suprised at the great reception with this little set...

The circuit is a divider by 64 used in many RF applications like as satellite receiver, digital tuners, frequency counters, PLL, etc. The heart of circuit is an IC named SAB6456, but you can use SDA2101 or other equivalent chips. Each output is NOT of the....

Companies usually purchase one type of telephone for all employees, which is understandable, especially if they obtain a discount for buying in quantity. One ringer sound for everyone can pose a problem, though, if the sound of a ringing phone makes a dozen....

This circuit will activate a relay when light falls to a preset level. Light level can be adjusted with VR1 and the relay contacts may be used to operate an external light or buzzer...

Fuzz is one of the classic guitar effects, and this simple circuit generates it quite well. The circuit is so compact that it can be built into guitars or amps that do not have built in fuzz to add that capability to the instrument. The circuit does not use....

The diac is a common component used to trigger triacs. The construction of a diac is similar to that with a transistor, but with both junctions doped to similar levels so that the two junctions' revers break down characteristics are similar. This is a fun....

In many applications, a single on/off button switches the power supply on or off. Usually, the system switches off regardless of the processing function or workload the microcontroller or DSP circuit is currently handling. The small circuit in Figure 1 is....

In this circuit the gain is provided by a FET type op-amp. I have used an LF351, which may be hard to obtain, but the TL071CN or TL081CN may be used and have a faster slewing rate than the LF351. The Maplin order codes are RA67X and RA70M respectively. The....

Who would like to build a sidetone oscillator with a minimum amount of parts should try the NE567 integrated circuit. The NE567 is a PLL circuit with an internal VCO for a operating frequency less than 500 kHz and it is normally used as an audio tone....

This is a fun and non-dangeros project for those people who like to throw projectiles magnetically. It simply works by placing a ferromagnetic projectile at one end of a coil and pulsing some power in it. The trick is to switch off power when the projectile....

The SPC2 is a solar power center, it can be used to handle all of the power functions for small 12 Volt solar powered devices. It contains a photovoltaic charge controller and a low voltage load disconnect circuit. The low voltage disconnect has a load....

I've taken the classic Fuzz Face circuit and added optical temperature compensation. This ensures that the output stage is biased at half the supply voltage regardless of variations in the transistors, particularly those caused by temperature. Tweaks:....

This circuit generates MIDI clocks and start/stop messages...

With this circuit we can create a altered sound of siren. The oscillator IC1a-b is constituted by two gates NAND, oscillating in very low frequency. This oscillation drive the IC2, that is a electronic switch, which opens and closes in the rythm of....

Here is a simple transmitter that when connected to a phone line, will transmit anything on that line (execpt the dial tone) to any FM radio. The frequency can be tuned from 88 to about 94Mhz and the range is about 200 feet. It is extremely easy to build and....

The first 5 circuits described in the following sections were reverse engineered from commercial HeNe power supplies. There may be errors in transcription as well as interpretation. In many cases, the transformer secondary voltage was not marked and....

Fan noise is becoming a significant issue as electronic equipment increasingly enters the office and the home. Noise is proportional to fan speed, and the airflowhence, fan speednecessary for cooling is less at low ambient temperatures. Because ambient....

This circuit produces a sound similar to a factory siren. It makes use of a 555 timer Ic used as an astable multivibrator of a center frequency of about 300Hz. The frequency is controlled by the pin 5 of the IC. When the supply is switched ON, the....

Video-DVM is a very cheap DVM that shows how an output as complex as a videocomposite signal can be generated entirely in software: two I/O pins and three resistors are all the hardware required. Connected to any TV set it displays voltages, included max and....