Bipolar junction Transistors

The invention of the junction transistor has changed great revolution in the electronics world. The bipolar transistor was invented by Shockley in the year of 1950. Transistors and all semiconductor devices have many advantages, so the electronics world is growing with semiconductors. Transistors are very small, have less weight, not affected by shock and vibration.

The transistor has three terminals which are collector, base and emitter. The structure of the transistor is P-N-P, consisting of N- region and sandwiched between P regions. The terminals are used for three different functions. The emitter is used to emit holes or electrons, the collector is used to collect the holes or electrons, and the base is used to support the emitter and collector.

The input characteristics of transistors are about 0.4 V to 0.5 V it also depends upon their construction. The saturation voltage is about 0.7V to 0.8V. When above 0.8V maybe rise to high values so that the transistors may get destroyed. The output characteristics of transistors are holes arriving at the collector are pulled out of the collector by the positive of the battery to produce the collector current. We can find both characteristics of the transistor from the plot.

The whole electronic device must have transistors because transistors play a vital role in electronic devices. After the invention of transistors, the integrated circuit developed.