# Capacitor charging/discharging waveform confusion

This is the circuit:

At t=0s, switch is moved to position 1 and the time constant= 1ms

At t=10ms, switch is moved to position 2, it is assumed there is no leakage current

At t=20ms, switch is moved to position 3 and the time constant is 1.5ms

The waveforms of position 1 and 3:

So I understand what's going on before 10ms but what's confusing me is after it, so if the time constant after 10ms(position 3) is 1.5ms then after five time constant where the capacitor is supposed to be fully discharged then must be at 1.5x5 = 17.5ms but on the waveform it looks like it's saying after five time constant, the capacitor is fully discharged at 22.5ms, so what's going on ?

• I think there's some confusion with the timing of the switch. it looks to me as though it switches from 1-2 sometime between 5ms and 10ms, and then from 2-3 at 10ms. – brhans Jan 10 '18 at 23:05
• But why the capacitor is discharged at 22.5ms ? five time constant after 10ms must be 17.5ms – BigRedMachine Jan 10 '18 at 23:09