Amateur Extra › E5 Electrical Principles › E5B04
E5B04
What is the time constant of a circuit having two 220-microfarad capacitors and two 1-megohm resistors, all in parallel?
Pick an answer to check it.
Answer: D. 220 seconds
Two 220 uF capacitors in parallel add to 440 uF. Two 1 megohm resistors in parallel give 0.5 megohm. Time constant = R x C = 0.5 x 10^6 x 440 x 10^-6 = 220 seconds.
Tip: Tau = R x C.