What Are the RL Discharge Time Constants for Open and Closed Switch States?

[Kev1n]

1. circuit consists of 10v supply, a switch, R1 (200ohm), R2 (100ohm) in series with a 1H inductance. with R3 (200ohm) across R1 and Inductance. I have to work out the time constants when switch is open and when closed.



2. when closed I have used 1 time constant = t = L/R, then 5 x L/R. I struggle now with the open formula



3. t= 1/200 = 0.005s anf 5 x L/R = 0.025s - using 200 ohm as rt for R2 & R3 as equivalent of series. Now struggling with open switch is it just the same with Rt being 266.67 ohms

 

[anathema]

?

Hi there!

Based on the information provided, it seems like you are working with a series RL circuit. In this type of circuit, the time constant can be calculated using the formula t = L/R, where L is the inductance in henries and R is the total resistance in the circuit.

When the switch is closed, the total resistance in the circuit is given by R1 + R2 + R3. So the time constant in this case would be t = 1H / (200Ω + 100Ω + 200Ω) = 0.002s.

When the switch is open, the total resistance in the circuit is given by R1 + R2. So the time constant in this case would be t = 1H / (200Ω + 100Ω) = 0.003s.

I hope this helps! Let me know if you have any further questions.