NPN common-emitter amplifier

Scenario

The NPN common-emitter amplifier is the first transistor circuit every electronics student builds. Schematex renders it from a five-line SPICE netlist — the same format used in LTspice, ngspice, and Cadence — with automatic component placement and rail routing, so the diagram matches the hand-drawn textbook version without any manual layout.

Annotation key

• circuit "..." netlist — enables netlist parsing mode (SPICE syntax)
• V1 vcc 0 9V — voltage source named V1, positive terminal at node vcc, negative at 0 (ground), value 9V
• Rc vcc c 2.2k — resistor Rc between nodes vcc and c with value 2.2 kΩ
• Rb vcc b 100k — base bias resistor between vcc and node b
• Q1 c b e npn — NPN BJT transistor: collector=c, base=b, emitter=e
• Re e 0 1k — emitter degeneration resistor between node e and ground

How to read

The supply rail (Vcc = 9 V) connects to the top of both resistors. Rc is the collector load; the output signal is taken across it. Rb biases the base into the active region. Re provides emitter degeneration for stability. Q1 amplifies a small base current into a large collector-to-emitter current flow. The auto-layout positions Vcc at top, ground at bottom, and Q1 in the center.