Random circuits

Here are some of over 800 projects from our free circuit diagrams database. For more, try browsing categories menu on the left.

Ultra Bright LED Lamp

This ultra-bright white LED lamp works on 230V AC with minimal power consumption. It can be used to illuminate VU meters, SWR meters, etc. Ultra-bright LEDs available in the market cost Rs 8 to 15. These LEDs emit a 1000-6000mCd bright white light like welding arc and work on 3 volts, 10 mA. Their maximum voltage is 3.6 volts and the current is 25 mA. Anti-static precautions should be taken when handling the LEDs.... [read more]

Mains Operated LED Circuit Schematic

Here is a simple and powerful LED circuit that can be operated directly from the AC 100 volt to AC 230 Volts mains supply. The circuit can be used as mains power locator or night lamp etc.. The resistor R1,R2 and capacitor C1 provides necessary current limiting. The circuit is sufficiently immune against voltage spikes and surges.... [read more]

Guitar Amplifier

The aim of this design is to reproduce a Combo amplifier of the type very common in the sixties and the seventies of the past century.... [read more]

One-IC two-tones Siren

This circuit is intended for children fun, and is suitable to be installed on bicycles, battery powered cars and motorcycles, but also in models and other games.... [read more]

18W + 18W Stereo Hi-Fi Audio Amplifier (TDA2030)

2 x 18W Hi-Fi Stereo Power Amplifier based around two TDA2030 ICs. It has good input sensitivity, low distortion, good operating stability and full protection against overloads and output short-circuits. It can be used as a booster amplifier for existing small systems or to drive a second pair of speakers besides the ones already connected to the system. The board needs a symmetrical power supply of ±18Vdc/3A and can be connected to loads of 8 or 4 Ohm.... [read more]

Controlling a relay with a digital logic level.

The schematic illustrates 4 methods of controlling a relay with a digital logic signal.... [read more]