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A line with two angled leads inside a circle, one carrying an arrow.
Also known as: Transistor symbol, BJT symbol, NPN symbol, PNP symbol
A bipolar transistor is drawn as a vertical bar with two angled leads, one of which carries an arrow. The arrow's direction is the whole content of the symbol: pointing out means NPN, pointing in means PNP, and nothing else on the page distinguishes them.
Marks a bipolar junction transistor: a three-terminal component in which a small base current controls a much larger current between collector and emitter.
Contexts: Electrical equipment
Names its three terminals base, collector and emitter. The base is the lead meeting the flat bar; the emitter is the lead carrying the arrow.
Contexts: Electrical equipment
Distinguishes NPN from PNP solely by the emitter arrow's direction — pointing away from the base for NPN, toward it for PNP. Substituting one for the other in a circuit does not work.
The single most consequential arrow in schematic reading, and the one most often misread.
Contexts: Electrical equipment
Is drawn with or without an enclosing circle depending on house style; the circle historically indicated a discrete packaged device rather than one formed on an integrated circuit.
Contexts: Electrical equipment
A short vertical bar with a wire meeting its middle from the left, and two wires leaving its right side at opposing angles, the lower one carrying a small arrowhead; often enclosed in a circle.
A fuller structured visual breakdown is not yet documented for this symbol.