FM Voice Transmitter

The following diagram is the circuit diagram of voice transmitter which use FM signal carrier to transmit the vioce signal to the FM receiver device. Components List: R1 = 4.7K R2 = 330 ohm C1 = 0.001uF (1nF) C2 = 10-40pF C3 = 4.7pF Q1 = 2N3904 L1 = see text Misc = Electret mike,… Read More »

Low Forward-Drop Rectifier

This is the circuit diagram of low forward-drop rectifier. A TMOS power FET (Q1) and a LM393 comparator provide a high-efficiency rectifter circuit. When VA exceeds VB, U1’s output becomes high and Q1 conducts. Conversely, when VB exceeds VA, the comparator output becomes low and Q1 doesn’t conduct.

Load Cell Amplifier

I’ve found some interesting schematic of load cell amplifier. As we know, load cell amplifier is pretty expensive with fair price range of 100-300 USD. You may built your own load cell amplifier to get the lower cost. Here the two scheme diagram of load cell amplifier circuit: Load Cell Amplifier using AMP04: source: http://cgi.ebay.com/Load-Cell-Amplifier-Improved-Better-Stability-New-/350451149452

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 »

Easy FM Tracking Transmitter

This is an easy FM tracking transmitter circuit project :). The scheme designed by Tony van Roon, and here the FM transmitter tracker diagram: Components List: R1 = 10K C1 = 100uF/10V C2 = 10nF C3 = 4-40pF trimmer capacitor C4 = 4.7pF IC1 = LM3909 Q1 = 2N3904 NPN transistor LED1 = Red LED/or… 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 »

Touch Alarm System

Touch alarm circuit is widely used for security, which is installed on the door. The advantages of this alarm is because the cost is cheap and difficult to detect by burglars / intruders. The following is an example of a touch of alarm circuit which is designed by Tony Van Roon. Components List: R1 =… 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: