Re: Cpacitor discharge

Tom Bruhns wrote:
On Feb 16, 2:32 pm, ehsjr <e...@xxxxxxxxxxxxxxxx> wrote:

Andrew Edge wrote:

<snip>

Hi Tom.

Lessee...the OP stated that the current is constant, not i=v/R.

For your information a Capacitor is an open circuit to a constant
current. So a capacitor generating constant current is impossible.

So you are saying this circuit won't work,
within any time limits, whatsoever:

/
+12 ----o o-----+--->|---+
| |
[R] |
| |
+--->|---+ I -> ~ 10 mA
| | -----
[1F] +---In|LM317|Out---+
| ----- |
| Adj [120R]
| | |
| +---------+
| |
| [R]
| |
Gnd -----------+---------------------------+


Check on Kirchoff's current law on the capacitor leads.
I hoped someone would have told him that.

The op is discharging a cap through an active load
which he says draws constant current. Such a circuit
is shown above.

After the switch has been closed for sufficient time
to fully charge the capacitor, it is opened. Will
the discharge be constant current, or does the circuit
suddenly lose the ability to regulate?

Ed

<snip>



You don't really think your logic will matter to him, do you, Ed?


I suppose not.


Note that he wrote, "For your information a Capacitor is an open
circuit to a constant current." That would mean that in a loop
comprising a constant current source, a capacitor, and a resistor,
there would be no current through the resistor...

Sigh.

Yup. I still have't figured out how to charge a
capacitor from a constant current source using
his gem of an idea.

Maybe it's a flux capacitor? :-)

Ed


Cheers,
Tom

.

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