Transistor

/ˈtrænzɪstər/

noun … “Semiconductor device for controlling current.”

Transistor is a semiconductor component used to amplify or switch electronic signals and electrical power. It is the fundamental building block of modern electronic devices, including logic gates, microprocessors, memory, and analog circuits. Transistors control current flow through their terminals—typically called the emitter, base, and collector (for bipolar junction transistors) or source, gate, and drain (for field-effect transistors).

Key characteristics of Transistor include:

• Switching: can turn current on or off, enabling digital logic operations.
• Amplification: can increase the power or voltage of a signal.
• Semiconductor material: usually silicon or germanium.
• Types: bipolar junction transistor (BJT) and field-effect transistor (FET) are the most common.
• Integration: billions can be embedded in modern microchips to implement complex circuits.

Workflow example: Using a transistor as a switch:

-- NPN BJT switch
if input_signal == HIGH:
    transistor.base_current = small_current
    transistor.collector_emitter_current = large_current
else:
    transistor.collector_emitter_current = 0

Here, a small base current controls a larger current through the transistor, enabling digital switching or signal amplification.

Conceptually, a Transistor is like a valve for electricity: a small control signal determines whether a larger flow of current passes through.

See Logic Gates, CPU, Semiconductor, Amplifier, Switch.