Author Archives:


 

Active DC Voltage Doubler

Here is the circuit diagram of active DC voltage doubler which used to increase the DC voltage. This circuit drives relays of 24 and 18VDC from a 12V power supply. Use this circuit can be work with almost any PNP or NPN power transistor, of course the transistor with specific characteristic similar to the transistor… Read More »

Basic Theory of DC to AC Inverters

This document explains about Basic Theory of DC to AC Inverters. Title: “The ABC’s of DC to AC Inverters”, arranged “by Electronic’s Department of Northen Alberta Institure of Technology. This document will show you the basic theory of DC to AC inverters, about the circuit’s works, the calculation to build DC to AC inverter and… Read More »

100W Audio Amplifier with Transistor BDW83D/BDW84D

Here is the circuit diagram of 100W audio amplifier which using power transistor BDW83D and BDW84D for the final amplification. It uses dual polarity power supply to work. Copyright belong to Smart Kit. The circuit should be seen like this: This is an exceptionally well designed amplifier, with a lot of power reserve, high fidelity,… Read More »

Mini FM Transmitter

This is a mini fm transmitter circuit. I think this is the simplest one. Simple, easy and of course… inexpensive… The supply voltage is between 1.1 – 3 Volts with power consumption is 1.8 mA at 1.5 Volts. This circuit should be able to cover  30 – 50 meters of range max. at 1.5 Volts.… Read More »

Electronic Buzzer with IC timer NE555

This easy electronic buzzer circuit built based on timer works for gaining the frequency. The IC timer NE 555 used as astable multivibrator operating at about 1kHz and produces a sound when switched on. The sound frequency can be adjusted by varying the 10K resistor. You may change the 10K resistor with variable resistor.

Emergency Light + Alarm

This is the circuit diagram of emergency light included the alarm circuit to show you that there is no power source in your building due to shutted down or short circuit. When the electric in your home/company has been shutted down for maintenance and or shutted down due to short circuit, you may need this… Read More »

Low Noise Portable Mic Preamp

This is the circuit diagram of portable mic preamp. This circuit consumes low current supply (about 2mA), so will have a long battery life for supplying the circuit. Harmonic distortion is about 0.1% @ 1V RMS output for all frequencies. Maximum input voltage (level control cursor set at maximum) = 25mV RMS. Maximum input voltage… Read More »