# Discharging of Electrolytic capacitors

#### Electronic_Maniac

Joined Oct 26, 2017
251
Hi all,

Consider the below circuit

I am applying the pulse 3b for 12V system. The pulse waveform is as mentioned in the ISO standard page 16 : http://www.compel.ru/wordpress/wp-content/uploads/2017/05/ISO-7637-22011E.pdf

this is my waveform at across C14.

My question is how does the capacitor discharge? Through which component does the current flowing during capacitor discharge?

Please explain in simpler terms for easy understanding.

Thanks

#### ericgibbs

Joined Jan 29, 2010
9,136
hi EM,
I would suggest when you have a LTS query you post your asc file and any non standard models.
It is a pain to redraw an existing circuit.

If U5 has zero internal resistance, the cap will discharge back thru U5

E

Update:
So that we know which node the plot is showing.

#### ericgibbs

Joined Jan 29, 2010
9,136
hi EM,
Use LTS to measure/plot the current in U5.
Or you can add a 0.001R resistor is series with U5, measure voltage across it and the current thru it.
E

#### Electronic_Maniac

Joined Oct 26, 2017
251
hi EM,
I would suggest when you have a LTS query you post your asc file and any non standard models.
It is a pain to redraw an existing circuit.

If U5 has zero internal resistance, the cap will discharge back thru U5

E

Update:
So that we know which node the plot is showing.
@ericgibbs Sure thanks. I will share henceforth. What if I have a diode between the supply and E-Cap C14. Now, how will C14 discharge? What would be the path?

#### Electronic_Maniac

Joined Oct 26, 2017
251
Can someone explain What if I have a diode between the supply and E-Cap C14. Now, how will C14 discharge? What would be the path?

#### crutschow

Joined Mar 14, 2008
23,826
Can someone explain What if I have a diode between the supply and E-Cap C14. Now, how will C14 discharge? What would be the path?
There is no path, so ideally it will never discharge.
In a real circuit the diode and capacitor leakage would eventually discharge it.

#### ericgibbs

Joined Jan 29, 2010
9,136
hi,
It would be helpful if you told us what is the purpose of the project.
Is it electronic ignition for a vehicle.?
E