Every diode component has an anode A and cathode K, but each uses a distinct symbol and model:
- Diode — general-purpose p-n diode.
- Schottky diode — low forward-drop diode for fast switching.
- LED — light-emitting diode; arrows on the symbol indicate emission.
- Zener diode — diode intended for reverse-breakdown operation.
- Varactor diode — reverse-voltage-dependent capacitance.
- DIAC — bidirectional trigger diode.
The Model parameter selects the electrical model. Generic models are demonstrative; import the manufacturer model for a specific part.
Tersa provides NPN, PNP, Darlington NPN, and Darlington PNP devices. Pins are base B, collector C, and emitter E. A single BJT can define initial VBE and VCE values and enable initial conditions.
The emitter arrow points out for NPN and in for PNP. A Darlington uses its own compound model rather than two independently placed BJTs.
- NMOS / PMOS — four-pin MOSFETs with
D,G,S, andB. - N/P VDMOS — three-pin power MOSFETs.
- N/P JFET — field-effect transistors with a p-n junction gate.
- MESFET — RF field-effect transistor with a Schottky barrier.
- FET subcircuit — wrapper for an imported multiparameter subcircuit model.
Choose a compatible model before simulation. Tersa keeps a stable pin order and maps it to the order required by .model or .subckt.
A five-pin ideal operational amplifier with IN+, IN-, OUT, V+, and V-. Use it to verify a topology. For bandwidth, slew rate, noise, and saturation, attach a real amplifier model.
- Voltage-controlled switch: power pins
1,2and control pinsC+,C-. - SCR: anode
A, cathodeK, gateG. - TRIAC:
MT1,MT2, gateG.
These are nonlinear components. Transient and HB analysis depend on a suitable model, initial conditions, and a realistic control source.