PNP transistor meter check: (a) forward B-E, B-C, resistance is low; (b) reverse B-E, B-C, resistance is ∞
Bipolar transistors are constructed of a three-layer semiconductor “sandwich,†either PNP or NPN. As such, transistors register as two diodes connected back-to-back when tested with a multimeter’s “resistance†or “diode check†function as illustrated in Figure below. Low resistance readings on the base with the black negative (-) leads correspond to an N-type material in the base of a PNP transistor. On the symbol, the N-type material is “pointed” to by the arrow of the base-emitter junction, which is the base for this example. The P-type emitter corresponds to the other end of the arrow of the base-emitter junction, the emitter. The collector is very similar to the emitter and is also a P-type material of the PN junction.
Read the complete article on BJT meter check here.
PNP transistor meter check: (a) forward B-E, B-C, resistance is low; (b) reverse B-E, B-C, resistance is ∞
Bipolar transistors are constructed of a three-layer semiconductor “sandwich,†either PNP or NPN. As such, transistors register as two diodes connected back-to-back when tested with a multimeter’s “resistance†or “diode check†function as illustrated in Figure below. Low resistance readings on the base with the black negative (-) leads correspond to an N-type material in the base of a PNP transistor. On the symbol, the N-type material is “pointed” to by the arrow of the base-emitter junction, which is the base for this example. The P-type emitter corresponds to the other end of the arrow of the base-emitter junction, the emitter. The collector is very similar to the emitter and is also a P-type material of the PN junction.
Read the complete article on BJT meter check here.
