Solve for and give Vb if the LED forward voltage is 3 and th

Solve for and give V_b if the LED forward voltage is 3 and the LED forward current is 10 mA. Label as needed.

Solution

APPLLY KVL IN LOOP

-Vb+200i+3300i=0

in problem given that i =10ma

-Vb=-500i-3

-vb=-[500i+3]

vb=500i+3

=500*10*10^-3+3

5+3

=8

so vb=8v