I am working on a circuit in which a load (a DC motor at 6V and 1A max current) needs to switch on or off. The controlling voltage (voltage at base) will be 0 to 3.3V.
I am planning to use
2N4401 transistor. My question is I can use my transistor in
saturation region when turned
on. I can select the resistor values accordingly. However, I am not sure when one mode is preferred over other and why.
Does operating in active region will cause my transistor to overheat as
Vce will be equal to excessive voltage left in the collector circuit.
For example, if Ib = 1mA, Current Gain of transistor (Beta) = 100, Vcc = 10V, my load resistance = 10 ohms. Then, a current 0.1 A will flow in collector circuit and my load will have 1 V drop. Then, the excess voltage of about 9 V will be across
Vce? Is this a problem for active region?. What if a connect a resistance of 50 ohm in series with my load in collector circuit? The resistance of 50 ohm will still keep the transistor in active region but it will reduce the
Vce to 4V.
What if I have a load and I want to push only a specific current and design my circuit to operate in
active region when turned on and
Vce will be calculated to be low so that power dissipation will be quite less.