What is Vcc, Vee, Vbb, Vdd and Vss stand for?

If you read a schematic diagram especially the IC pins, you will notice that there are certain pins that we do not really know what it stand for. They are all supply voltages. Vcc = Collector supply voltage, Vee = Emitter supply, Vbb= Base supply voltage, Vdd = Drain supply, Vss = source supply. Whenever the supply to a Transistor (or  TTL  IC circuit) is connected between the collector and ground it is a standard to notify it as Vcc. If you connect the supply between Base and ground we will call it Vbb and the same goes with Vee for emitter to ground.

Since there is no notion to identify ground (0) this method was simply adopted. The voltages can be negative or positive depending on the the device and the circuit configuration. This method is a standard specified by Institute Of Electrical And Electronics Engineer (IEEE).

4 Comments

1. 

   Steve Hearns

   April 23, 2010 at 11:46 pm

   Hi Jestine: I learned in electronic school during transistor theory operation that VCC means: Voltage Collector constant. I think engineers adopt their own fancy terms when they design IC circuits.

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2. 

   Pablo

   December 7, 2010 at 4:22 pm

   Vdd stands for FET Positive supply voltage
   Vcc stands for BJT Positive supply voltage
   Vss stands for FET Negative supply, ground
   Vee stands for BJT Negative supply, ground

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3. 

   kamarul

   July 12, 2012 at 11:10 pm

   so the point where VCC, Vee, Vbb is just a point....no electronic device????

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   • 

     Jestine Yong

     July 13, 2012 at 5:33 am

     Hi Kamarul,

     Those are points in IC legs and you need to download the IC datasheet to see those points.

     Jestine

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