Component Notes Resistors LED IC Socket Diode
Example Transistor Driver Circuits Lo Side Drive (NPN) Load La1 is connected to the +V supply (Hi) and then switched to ground (Lo) to turn on. (Positive Logic – High on the input turns the load on.) See far upper right example. Hi Side Drive (PNP) Load La2 is connected to ground (Lo) and then switched to +V (Hi) to turn on. (Negative Logic – Lo on the input turns the load on.) Lo side driver relay driver Darlington pair transistors are used in applications where Very heavy current loads need to be controlled. The darlington Configuration offers much higher current gain because the hfe of the device is the product of the hfe of the two transistors TR1 and TR2 . Opto-Isolators offer isolation which is not easily obtainable with any other device. When controlling very high voltages this provides Isolation protection for sensitive devices such as micro-controllers.