The circuit used in making simple Transistor Tester Combo-2 has only one IC.
Process1: Position the transistor to the three circuit
terminals of Circuit 1 (located either below of left of the terminal). Once
pointed, the red LED can then identify the PNP transistor base. This process
will lead to the emission of a green LED, which points to the base of the NPN
Process 2: Now that you are aware of the transistor type and
the base lead, simply position the transistor in the top circuit (Test 2). As
you properly place the collector, the emitter works perfectly. However, there
may be a chance to swipe leads in case if it fails to work. If the red and
green LED works it proves the transistor is functional correctly.Test
Process 3: The transistor is now ready to be placed in the
GAIN SECTION. Select either NPN or PNP. As you select, simply turn on the pot
and keep it turned as long as the LED is illuminated. However, as a matter of
practice be sure to check the value of the gain mentioned in the PCB.The probe located at the end of the board helps to
create square wave. Furthermore, this simple transistor tester probe is also efficient to testing audio
of any sorts.