| A | Ampere (AC rms or DC) | hie | Common emitter small-signal short-circuit input impedance (base input) |
| a | Ampere (peak) | hob | Common base small-signal open-circuit output admittance (emitter input) |
| B | Base electrode | hoc | Common collector small-signal open-circuit output admittance (base input) |
| BV | Breakdown voltage | hoe | Common emitter small-signal open-circuit output admittance (base input) |
| BVCOB | Breakdown voltage, collector-to-base junction reverse biased (emitter open) | hrb | Common base small signal open-circuit reverse transfer voltage ratio (emitter input) |
| BVCEO | Breakdown voltage, collector-to-emitter junction reverse biased (base open) | hrc | Common collector small signal open-circuit reverse transfer voltage ratio (base input) |
| BVCER | Breakdown voltage, collector-to-emitter junction reverse biased (specified resistance) | hre | Common emitter small signal open-circuit reverse transfer voltage ratio (base input) |
| BVCES | Breakdown voltage, collector-to-emitter junction reverse biased (base shorted) | isurge | Surge current |
| BVCEX | Breakdown voltage, collector-to-emitter junction reverse biased (base-emitter back biased) | IB | Average base current (DC) |
| C | Capacitance; collector electrode | Ib | Instantaneous base current (AC rms) |
| Ce | Internal collector junction capacitance. | ib | Base current (peak) |
| C(dep) | Depletion layer capacitance | mW | Milliwatt (Max., Average, or rms) |
| C(dif) | Diffusion capacitance | mw | Milliwatt (peak) |
| Cib | Input Capacitance, common base | NF | Noise figure |
| IC | Collector current (DC) | nsec | Nanosecond (Millimicrosecond) |
| Ic | Collector current (AC rms) | P | Power dissipation of all terminals (average total) |
| ic | Collector current (peak) | p | Power dissipation of all terminals (peak) |
| ICBO, ICO | Collector cutoff current (emitter open) | Pb | Power dissipation of base (average) |
| ICEO | Collector cutoff current (base open) | pb | Power dissipation of base (peak) |
| ICER | Collector cutoff current (specified resistance base-emitter) | Pc | Power dissipation of collector (average) |
| ICERV | Collector cutoff current (reverse voltage on base) | pc | Power dissipation of collector (peak) |
| IE | Average emitter current (DC) | Pd | Power dissipation of device (average) |
| Ie | Instantaneous emitter current (AC rms) | Pe | Power dissipation of emitter (average) |
| ie | Instantaneous emitter current (peak) | pe | Power dissipation of emitter (peak) |
| IEBO | Emitter cutoff current (collector open) | PIV | Peak inverse voltage |
| IF | Forward current (DC) | Q | Transistor |
| iF | Forward current (DC) | rb', rBB' | Internal base spreading resistance |
| iFr | Forward recovery current (specified instantaneous value) | RB | External base resistance |
| IO | Output current (DC) | RC | External collector resistance |
| IR | Reverse current (DC) | RE | External emitter resistance |
| iR | Reverse current (peak) | Rsat | Saturation resistance |
| iRr | Reverse recovery current (specified instantaneous value) | RL | Resistance, load |
| IZ | Average Zener current | T | Temperature |
| IZK | Zener knee current | t | Time |
| IZM | Zener maximum current | TA | Temperature, ambient |
| IZT | Zener test current | TC | Temperature, case |
| iZ | Instantaneous Zener current (AC rms) | TCBV | Temperature coefficient of breakdown voltage |
| K | Kilohm | td | Pulse delay time |
| LC | Conversion loss | tf | Pulse fall time |
| mA | Milliampere (average) | tfr | Forward recovery time |
| ma | Milliampere (peak) | Tj | Junction temperature |
| mAa-c | Milliampere (AC rms) | tP | Pulse time |
| mAd-c | Milliampere (DC) | tr | Pulse rise time |
| µA | Microampere (average) | ts | Pulse storage time |
| µa | Microampere (peak) | V | Volt (DC) |
| CL | Load capacitance | v | Volt (peak) |
| Cob | Output capacitance, common base | Va-c | Volt (AC) |
| Coe | Output capacitance, common emitter | VBB | Base voltage (DC) supply |
| E | Emitter electrode | VBE | Emitter voltage (DC) (base to emitter) |
| fab | Common base small-signal short-circuit forward current transfer-ratio cutoff frequency (emitter input) | VCC | Collector voltage (DC) supply |
| fae | Common emitter small-signal short-circuit forward current transfer-ratio cutoff frequency | VCEsat | Collector to emitter saturation voltage |
| fref | Reference frequency | VEC | Emitter voltage (DC) (emitter to collector) |
| fosc | Maximum frequency of oscillation | VEE | Emitter voltage (DC) supply |
| fpg | Power gain cutoff frequency | Vfe | Floating potential |
| Gb | Power gain (common base) | VF | Forward voltage drop |
| Gc | Power gain (common collector) | VO | Output voltage (DC) |
| Ge | Power gain (common emitter) | vO | Output voltage (DC) |
| gM, gFE | Static or DC transconductance | VPT | Voltage, punch-through |
| gm | Small-signal transconductance | VR | Reverse voltage (DC) |
| GM, GFE | Large-signal transconductance | Vr | Reverse voltage (peak) |
| hfb | Common base small signal short-circuit forward current transfer-ratio | VZ | Zener voltage |
| hfe | Common emitter small-signal short-circuit forward current transfer-ratio (base input) | W | Watts (Max., Average, or rms) |
| hFE | Common emitter DC short-circuit forward current transfer-ratio current gain (IC / IB) | w | Watts (peak) |
| HFE | Common emitter large-signal short-circuit forward current transfer-ratio | Zz | Zener impedance |
| hib | Common base small-signal short-circuit input impedance (emitter input) | Zzk | Zener impedance, knee |
| | | Zzt | Zener impedance, test |
