3A Switching Power Supply Regulator

This is the circuit diagram of 3A switching power supply regulator: Simple and cheap, the circuit built based on well-known IC regulator LM317 with current booster of power transistor 2N3782. Don’t forget to add heatsink especially for power transistor 2N3782.

300-2500Hz Audio Bandpass Filter

This is an audio bandpass filter circuit which will filtering the audio frequency from 300Hz to 2500Hz.. The lower and higher audio frequency will be cut off. Download the explanation here

Current Output Multiplier for 78xx Regulator

This is the circuit diagram of current output multiplier designed for regulator IC LM78xx. By default, the regulator ID 78xx series will give maximum current output 1A – 1.5A. To increase the current output of this regulator, you may consider to build this circuit. The circuit is simple, easy built and inexpensive. Parts list: R1,… Read More »

Cut Phone Line Detector

This cut phone line detector circuit is used to detect whether your phone line is active or not. Components List: R1,R2,R3 = 22M Ohms R4 = 2.2M Ohms C1 = 0.47uF/250V Mylar caps D1 = 1N914, NTE519, or other small signal diode Q1 = 2N3904, NTE123AP Q2 = 2N3906, NTE159 Q3 = IRF510, NTE2382,? MosFet

4 Transistor FM Tracking Transmitter

The following diagram is the FM tracking transmitter based on 4 transistors. No additional notes for this tracking transmitter diagram, try to discover this circuit by yourself.. 🙂 Components list: R1 = 100K Ohms R2 = 10 Ohms R3 = 47K Ohms R4 = 220 Ohms C1 = 4.7uF/16V C2, C5 = 1nF C3 =… Read More »

Tube Head Pre-amp

This is a simple and low cost Tube Head Vacuum Tube pre-amp circuit designed bu PAiA electronics: Vcc – Pin 1 IC1 +12v – Pin 8 IC2, IC3, IC4 -12v – Pin 4 IC2, IC3, IC4 Ground – Pin 8 IC1 IC1 – 4049 CMOS Hex Inverting Buffer IC2, 3, 4 – 5532 Dual Low-Noise… Read More »

Orange 125MK3 Guitar Mods

This document contains schematic diagram of Orange 125MK3 including the guitar preamp section, feedback and power amplifier section. Preview:

Automatic 9V Battery Charger

This is the scheme diagram of automatic 9V battery charger circuit, the parts list provided below the schematic image. The circuit was designed by Jan Hamer, translated by Tony Van Roon dan republished in this circuit diagram site. The circuit details are based on european standards: 120E, 150E, etc. The ‘E’ just stands for Ohms… Read More »


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