Practical takeaway
Diodes mainly control direction of current; transistors can switch or amplify signals. They are basic building blocks inside nearly every modern radio.
Electricity & Electronics
Diodes & Transistors
Explore two building blocks that steer, switch and control electrical signals.
TECHNICIAN FOUNDATION11 of 16
Technician exam focus
Recognize basic diode and transistor functions and common schematic representations expected for Technician study.
Control current with semiconductor devices
Diode
For ordinary circuit operation, a diode conducts current in its forward direction and blocks current in the reverse direction. Real diodes have a tiny reverse leakage current, but that is not the useful operating path being taught here.
Transistor
A transistor can act as an electronic switch or as an amplifier. A small change at its control terminal can change a larger current in another part of the circuit.
Why hams care
Rectifiers, power supplies, oscillators, amplifiers, switching circuits, and RF stages all use semiconductor devices.
STEMulation