3In1-test-set


Posted on Dec 14, 2012

This circuit is designed around a 4049 hex inverter/buffer. Two inverters are used ina dual-frequency signal-injector circuit, another inverter is used as a logic probe, and the remaining three inverters are used as a sensitive dual-input, audio-signal tracer. The signal-injector portion gates are configured as a two-frequency, pulse-generator circuit. Under normal conditions, the generator`s output frequency is around 10kHz, but when 52 is closed, the output frequency drops to about 100 Hz.


3In1-test-set
Click here to download the full size of the above Circuit.

The logic-probe portion is made up of U1c, the output of the inverter decreases. The low output of U1c reverse biases LED2, so it remains off. That low output also forward biases LED1, causing it to light. But when a logic low presented Ulc"s input, the situation is reversed, so LED2 lights and LEDl darkens. The audio-signal tracer portion is made up of the three remaining inverters which are configured as a linear audio amplifier to increase the input signallevelby a factor of 10 or 100. The amplified output signal feeds a miniature piezo element of audible detection.




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

ALKALINE CHARGER
SMS through Telephone with AT89S8252
807 and 1625 Valves as power amplifiers
Dc lamp dimmer
Inexpensive Pulse Generator For Logic Troubleshooting
Carrier-Operated Relay
DDS SigGen PS
am transmitter double side band
FM adaptor circuit for car stereo
SD/SDHC Card Interfacing with ATmega8 /32 (FAT32 implementation)
Pulse Circuits for Infrared LEDs and Visible Diode Lasers
TV audio circuit diagram TA8218AH
Battery voltage indication circuit



Top