TRANSISTOR TESTER - 2

TRANSISTOR TESTER - 2

Here is another transistor tester.

This is basically a high gain amplifier with feedback that causes the LED to flash at a rate determined by the 10u and 330k resistor.

Remove one of the transistors and insert the unknown transistor. When it is NPN with the pins as shown in the photo, the LED will flash. To turn the unit off, remove one of the transistors.