In a Series Op-Amp Regulator, given R1=4.0kΩ, R2=10kΩ, R3=4.9kΩ, VZ=3.6V, VIN=14V.

Assume IL=260mA, what is the power dissipation by transistor?

1 answer

To calculate the power dissipation of the transistor, we first need to calculate the output voltage of the regulator.

The output voltage is given by:

Vout = VZ * (1 + R2/R1) + IL * R3

Substituting the given values, we get:

Vout = 3.6 * (1 + 10/4) + 0.26 * 4.9
Vout = 12.84V

The voltage drop across the transistor is VIN - Vout = 14 - 12.84 = 1.16V

The power dissipation of the transistor is:

P = V * I = 1.16 * 0.26
P = 0.3016W or 301.6mW

Therefore, the power dissipation by the transistor is 301.6mW.