"VCC" stands for "Voltage at the Common Collector" and it is a term used in electronic circuits to refer to the power supply voltage that is applied to the collector of a bipolar junction transistor (BJT).
In a typical BJT circuit, the transistor has three terminals: the emitter, the base, and the collector. The emitter is usually connected to ground or a negative power supply, while the base is used to control the current flow through the transistor. The collector is used to collect the current that flows through the transistor.
The VCC voltage is the power supply voltage that is applied to the collector of the transistor. The voltage level of VCC is usually determined by the specific requirements of the circuit and the voltage rating of the transistor being used.
In digital circuits, VCC is often used as a reference voltage for the high logic level. For example, in a TTL (Transistor-Transistor Logic) circuit, a VCC voltage of 5 volts might be used to represent a logic high level, while a voltage close to 0 volts might be used to represent a logic low level.