Ultrasonic Motion Detector

This is a ultrasonic motion detector (or movement detector) circuit. The circuit claimed has a high movement sensitivity. Even air moving (hot air rising, wind blowing) will trigger it when the trimpot is set near the most sensitive position. The transmitter sends out a steady ultrasonic tone at 40kHz. At this frequency the wavelength is… Read More »

5V Regulated Solar Cell Power Supply

Powered with solar panel, the circuit will give you 5V pure regulated DC voltage. This solar cell power supply circuit is made up of an oscillator transistor as well as a regulator transistor. The solar panel charges the battery when sunlight is bright enough to generate a voltage above 1.9v. A diode is necessary between… Read More »

3-Rail (+12V) / (+5V) / (-5V) Regulated Power Supply

This circuit generates 3 source regulated voltages applying a minimum of electronic parts. The output DC voltage are +12V ; +5V and -5V. Diodes D2 and D3 conduct full-wave rectification, at the same time charging capacitor C2 on each halves of the alternating current cycle. At the same time, diode D1 with capacitor C1, and… Read More »

Electro-Harmonix Small Stone Phaser Guitar Effect

This is the schematic diagram of Electro-Harmonix Small Stone Phaser guitar effect pedal. The Small Stone is somewhat special in applying Operational Transconductance Amplifiers (OTA”s) for phase shift stages rather of opamps with variable resistors. All of the IC”s are house marked EH1048, but could be replaced with CA3094 that is a combination of an… 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 »

3A Switching Voltage Regulator based LM317HV

Above circuit diagram is a easy, simple and cheap switching voltage regulator which has capability to deliver adjustable voltage output range of 1.8V to 32V and static electric current of 3A. This regulator use adjustable regulator IC of LM317HV and a power PNP transistor of 2N3792.