chapter  18
28 Pages

Fault-finding in microprocessor systems

The base of the transistor is connected to the negative of the meter. When the positive lead is connected to either emitter or collector, a reading of between 20 and 30 indicates a good transistor. No other combination of connections should give a reading. For pnp transistors, connect the base to the positive lead of the meter (see Figure 18.8). A reading should be obtained when the negative lead is connected to either emitter or collector. Any other readings would indicate a faulty transistor.