вот Vcc - Voltage Collector Collector Vdd - Voltage Drain Drain Vee - Voltage Emitter Emitter Vss - Voltage Source Source
Vcc -- For TTL circuitry, this is the +5 volts which sits on the collector of the bi-polar transistor output circuit. Vee -- For TTL circuitry, this is the GND which sits on the emitter of a bi-polar transistor output circuit. Vdd -- For CMOS circuitry (like the PIC) this is the +5 (or +3) voltage that sits on the 'drain' of a MOS-FET transistor output circuit. Vss -- For CMOS circuitry, this is the GND that sits on the 'source' of a MOS-FET transistor output circuit.
Positive voltages: Vcc- Positive supply voltage of a Bipolar Junction Transistor. Vdd- Positive supply voltage of A Field Effect Transistor
Negative voltages/ground: Vee- Negative supply voltage of a Bipolar Junction Transistor. Vss- Negative supply voltage of A Field Effect Transistor.
The letters c,d,e and s originated from the name of the legs of the transistors Collector, Drain, Emitter and Source.
