could anyone help me out in doing this problem plsss ...wat is the base current required to drive the tip120 transistor in to ON state...i tried looking in to data sheet n could not find. i dont know whether a formula is to be used to calculate the base current. i have attached the data sheet below so could anyone help me out plsssss
It depends on how much is the load current and if you want it to be saturated or not.
1) Its minimum DC current gain is 1000 when it has 3V from its collector to its emitter. So with a collector current of 3A the base current must be at least 3mA.
If you want it to saturate with a saturation voltage loss of up to 2V (quite poor) and a collector current of 3A then its base current must be at least 3A/250= 12mA.
If you want it to saturate with a saturation voltage loss of up to 4V (very poor) then its base current must be at least 5A/250= 20mA.
If you want it to saturate with a lower voltage loss then give it more base current.