Transistor Tester using 555 IC
Posted by Rohan on Friday, July 18, 2014 with No comments
The 555 operates at 2Hz. Output pin 3 drives the circuit with a positive then zero voltage. The other end of the circuit is connected to a voltage divider with the mid-point at approx 4.5v.
This allows the red and green LEDs to alternately flash when no transistor is connected to the tester.
If a good transistor is connected, it will produce a short across the LED pair when the voltage is in one direction and only one LED will flash.
If the transistor is open, both LED’s will flash and if the transistor is shorted, neither LED will flash.
(NOTE - In pics below i have used a series of resistances to make 33K resistance )
This allows the red and green LEDs to alternately flash when no transistor is connected to the tester.
If a good transistor is connected, it will produce a short across the LED pair when the voltage is in one direction and only one LED will flash.
If the transistor is open, both LED’s will flash and if the transistor is shorted, neither LED will flash.
COMPONENTS USED :
1.one 555 IC
2.two 1N4148 diode
3.one 33K resistor
4.four 220 Ohm resistance
5.one Red LED
6.one Green LED
7.one 10uF Electrolytic Capacitor
8.one 9-12v Supply
(NOTE - In pics below i have used a series of resistances to make 33K resistance )
0 comments:
Post a Comment