If I have a BJT with a max Ic rating of 200mA and I drive in a base current which when multiplied with hfe, results in a theoretical Ic value of more than 200mA, will the collector actually draw in more than 200mA and get damaged, or will the collector keep drawing a max cap of 200mA? Is it safe to drive a transistor using base currents which would normally generate Ics higher than the data sheet cap recommendations?
Transistor Collector current issue
transistors
Best Answer
A transistor doesn't have a current limiter - it will pass whatever current the surrounding circuit permits, if the base current x gain permits that current.
The Maximum Collector Current rating just means that the part is designed to carry that much current without damage.
When determining the maximum current a transistor can carry, you must also look a the collector/emmitter voltage drop to determine the power dissipated in the transistor.
You must design the surrounding circuit to ensure that none of the transistor's maximum ratings are exceeded.