Tone Generator by 2N4891

August 19th, 2008


This be Basic Tone Generator by UJT Transistor 2N4891 numbers. By it s can give with small-sized loudspeaker s have a voice electric loud bell moderately. The value of C1 be valuable a little for enhance the speed in the package and disgorge to load. In each round (Cycle) that get be sound frequency at shine depart a loudspeaker. By can fine sound frequency get with R2 - 100K the value Resistance low tall frequency. But if the value is Resistance the tall low voice frequency. This circuit has can to develop next again. Request enjoy something sound electric bell this circuit please sir, be lucky.

250W Computer supply china circuit

August 18th, 2008


A friend of me inquires about power supply switching circuit. Which produce from the People’s Republic of China model the circuit is all. Be the Chinese seek difficult many circuits. I then try to seek many circuit. Meet this circuit. Think may yes. Because of there is the Chinese controls all equipment detail. But must beg one’s pardon friends. With that model the circuit not clear however might enough in rows the profit ? A few the a little when see good as a result see equipment position understands not difficult extremely. There is the integrated circuit TL494 with and can give voltage output get +12V,-12V and +5V support using has usually.

Random Number Generator by IC 4017 and 4011

August 16th, 2008


This be Random Number Generator Circuit there is the character is 10 LED Flasher by use IC 4017 and IC 4011. For the 4017 IC is a 16-pin CMOS decade counter. It takes clock pulses from the clock input, and makes one of the ten outputs come on in sequence each time a clock pulse arrives. Usability press S1 for LED Flasher respectively. By pressure (Close) S1 make LED all stick dim (Dimly). When liberate (open) S1 make LED stick bright at LED any one to one’s fate. Besides value expansion C1 be 4.7uF make LED flasher slow down. The detail is other invite friends see in the circuit leisurely.