Transistor Schematic Symbols
In this article, we show the schematic symbols for various types of transistors.
So below are the tables for various types of transistors.
BJTs |
JFETs |
MOSFETs |
Enhancement Type |
Depletion Type |
Power MOSFETS |
UJTs |
Phototransistors |
Bipolar juction transistors (BJTs) are current-controlled transistors composed of up 3 terminals: the base, the collector, and the emitter.
NPN BJTs are bipolar junction transistors that are composed of 2 N-material junctions and 1 P-material junction.
PNP BJTs are bipolar junction transistors that are composed of 2 P-material junctions and 1 N-material junction.
This fundamental composition difference between NPN and PNP transistors gives them different operation when controlling them.
JFET transistors stand for junction field effect transistors.
JFETs are voltage-controlled transistors composed of 3 terminals: the gate, the drain, and the source.
N-channel JFETS are composed of a majority of electrons, while P-channel JFETs are composed of a majority of holes. This internal composition difference differs their operation.
MOSFET transistors stand for metal oxide field effect transistors.
There are chiefly 2 types of MOSFETs: enhancement-type and depletion type. Both types come in N-channel and P-channel form.
Power MOSFETs are MOSFETs designed to handle a much larger power load (current and voltage) than regular MOSFETs. Power MOSFETs come in N-channel and P-channel types.
Unijunction transistors (UJTs) are three-lead transistors that act exclusively as electrically controlled switches; they are not used as amplifiers.
Unijuction transistors come in N-channel and P-channel types.
Phototransistors are transistors that are turned on and operated by light. When there is sufficient light to the base of the transistor, current conducts across the emitter-collector terminal.
Phototransistors come in NPN and PNP varieties.
Related Resources
Electronic Schematic Symbols
Capacitor Schematic Symbols
Types of Transistors
BJT vs FET (Transistors)
JFET vs MOSFET (Transistors)