I have some general questions about the terminology used to describe Transistors.
Here’s what it says for one specific one I saw (PN2222):
Collector-Emitter Voltage (VCEO) - 40V
Collector-Base Voltage (VCBO) - 75V
Emitter-Base Voltage (VEBO) - 6.0V
Collector Current (IC) - 600mA
Now, I understand what the Collector Current is, but I have no idea why the others are listed as a hyphenated version of two pins (eg, Collector-Base)… Any help please? ;D
VCEO = how much you can dump into the collector voltage wise
VCBO = hmm, cant find much on that one???
VEBO = max voltage tween base and emitter (it takes less than 1v to switch in most cases)
IC = how much amperage the transistor can pass
The terms VCEO, VCBO and VEBO are the OFF characteristics of the transistor.
They are also called the working characteristics.
For example VCEO is tested with a base current of 0 and a small collector current.
Since there is no base current the transistor is off and the resistance between
collector and emitter is high. Passing a small current into a high resistance
produces a high voltage. Once the voltage gets too high the transistor
breaks down and is no longer off. VCEO is sometimes called V(BR)CEO.
In order for the device to switch on an off reliable you need to be
below the working ratings. The VCE in your circuit should not exceed the
VCEO of the device.
A good place to find these details is the datasheet. For each of these parameters
the test conditions are listed. Take a look at the On-Semi 2N3904 datasheet.
(* jcl *)
These are ratings that the transistor can withstand, any more and they will be damaged or destroyed.
So collector - base voltage is the maximum voltage there can be between the collector and the base. In your example this is 75V which means you are safe with any arduino use. However it tells you that if you want to switch say a 100V load then it would be too much for the transistor.
The same goes for the emitter - base voltage.