Theremin Music Instrument

The following diagram is the Theremin music instrument effect. A guitar or instrument amplifier is an ideal companion unit for the theremin; either one allows bass or treble boost, as desired, and fuzz (distortion) or reverberation (if these features are incorporated in the amplifier”s circuit). Simply provide a suitable cable plug and connect the theremin”s… Read More »

Telephone Amplifier using LM386

The following diagram is the circuit diagram of telephone amplifier, build based small amplifier IC LM386. This is a easy build telephone amplifier There is no extra electrical power supply required to power up the telephone amplifier circuit, as it draws power from the telephone line itself. The amplifier will supply fairly very good volume… Read More »

5 Band Graphic Equaliser

This is the design diagram of 5 band graphic equaliser circuit build using operational amplifier chips, the NE5532 or LM833. The op-amp ICs is a good choice because of inexpensive and comes with fairly good quality output. Each IC contains dual op-amps circuit, so you will need 4 ICs of NE5532 or LM833 to build… Read More »

NiCd – NiMH Battery Charger

Here is the simple and low cost NiCd and NiMH battery charger circuit which can be used for various battery type and size. This battery charger use a regulator IC of LM317. Schematic diagram: The charge will start if a battery is connected between pins JP1-JP4 or JP2-JP4 or JP3-JP4. For example, if a battery… Read More »

2 x 1.2W Dual Power Amplifier with KA2214

This is another stereo / dual power amplifier circuit with power IC KA series. This amplifier delivers dual power output (stereo) at 1.2W for each channel. General The KA2214 is a monolithic integrated dual audio power amplifier in a 14-pin plastic dual in line package. It is designed portable audio sets.

Color Detector

This is the color detector / sensor circuit diagram. This circuit will sense eight colors that are: green, red and blue (as primary colours); magenta, cyan and yellow (as secondary colours); and black and white. It’s will be very useful for robotics project. The circuit is based on the fundamentals of optics and digital electronics.… Read More »

Safe Constant Current Source

In the above circuit diagram, a CMOS operational amplifier (op-amp) controls the current via a P-Channel HEXFET power transistor (IRF9520) to maintain a constant voltage across R1. The current is given by: 1 = VREF/R1. The benefits of this configuration are:

Six LED Stereo VU Display

The following image is the scheme diagram of six LED stereo VU display circuit which build using Dot/Bar Display Driver IC LM3915. This VU display should be connected before amplifier module circuit. You may connect this circuit at pre-amp output, tone control input/output or equaliser input/output. This circuit powered with 12V DC supply. About LM3915:… Read More »


Page 1 of 5812345...102030...Last »