New thought to me.

[Warren Weber]

Just thought about this today. How do I figure the instantaneous watt power
available from a charged capacitor, Have been in electronics and repair
since 1943. But this thought never occured to me. As a Charged 1000mfd with
12 volts would be. And them I assume a 4000 mfd would have 4 times the watts
available. Any ideas on this? Warren
--

 

[Jamie]

Warren Weber wrote:

Just thought about this today. How do I figure the instantaneous watt power
available from a charged capacitor, Have been in electronics and repair
since 1943. But this thought never occured to me. As a Charged 1000mfd with
12 volts would be. And them I assume a 4000 mfd would have 4 times the watts
available. Any ideas on this? Warren
With the Last name of "Weber" being an SI unit, "WEBER"

I would thing with your fame the answer should be there.

E = 1/2 * C * V^2

Now I'm not as good at ASCII text for math as some of the
others here..
E= Energy stored in Cap.
1/2 = 0.5
C = capacitance.
V = voltage across the cap squared.


--
"I'd rather have a bottle in front of me than a frontal lobotomy"
http://webpages.charter.net/jamie_5

 

[Phil Allison]

"Warren Weber"

Just thought about this today. How do I figure the instantaneous watt
power available from a charged capacitor,

** There is no such quantity.

There are quantities called:

1. Peak current.

2. Peak power.

3. Total stored energy in Joules.

Peak current is obtained if the cap is shorted - but no power is dissipated
into a short.

Peak power is obtained, for an instant, if the cap is discharged into a
resistance equal to its own internal resistance or ESR. For a 1000uF
electro, this might be around 0.1 ohms and the peak voltage will be half
that of the charged cap.

Stored Energy is the value in Joules given by :

E = 1/2 x C x V squared

So yes, more capacitance = more Joules, but more voltage is better as the
number is squared.



........ Phil

 

[BobW]

"Warren Weber" <hiview@bresnan.net> wrote in message
news:adWdnchJmN3chM_anZ2dnUVZ_vKunZ2d@bresnan.com...

Just thought about this today. How do I figure the instantaneous watt
power available from a charged capacitor, Have been in electronics and
repair since 1943. But this thought never occured to me. As a Charged
1000mfd with 12 volts would be. And them I assume a 4000 mfd would have 4
times the watts available. Any ideas on this? Warren
--

Warren,

First, you must realize the difference between energy and power. The amount
of energy stored is a measure of how much change or how much work can be
performed when all that energy is transferred to some other system. Power is
the rate of change of transfer of the energy (per unit time). Energy = power
* time.

A unit of energy normally used when discussing capacitors is the joule
(equivalent to the watt-second). One joule of energy transferred per second
is equal to one watt of power.

Your 4000uF cap stores 4x the energy of a 1000uF cap (at the same voltage).
However, the maximum power that can be delivered by any capacitor is more a
function of the caps' internal impedance and the external load. A 1uF cap
*could* deliver more power than a 4000uF cap, but it would poop out very
quickly because of its relatively low amount of stored energy.

Bob

 

[John Popelish]

Warren Weber wrote:

Just thought about this today. How do I figure the instantaneous watt power
available from a charged capacitor, Have been in electronics and repair
since 1943. But this thought never occured to me. As a Charged 1000mfd with
12 volts would be. And them I assume a 4000 mfd would have 4 times the watts
available. Any ideas on this? Warren

Total energy stored in a capacitor in joules is (C*V^2)/2,
with C in farads and V in volts.

So 1000 uF (0.001F) charged to 12 volts holds
(0.001*12*12)/2=0.072 joules (watt seconds).

4000 uF charged to 12 volts holds 4 times that energy or
0.288 joules.

--
Regards,

John Popelish

 

[Eeyore]

Warren Weber wrote:

Just thought about this today. How do I figure the instantaneous watt power
available from a charged capacitor, Have been in electronics and repair
since 1943. But this thought never occured to me. As a Charged 1000mfd with
12 volts would be. And them I assume a 4000 mfd would have 4 times the watts
available. Any ideas on this? Warren

Well ..... a capacitor stores ENERGY (joules) not power (watts).

The energy stored is 1/2 * C * V ^2

So a 4000 uF cap stores 4 times as much energy as a 1000 uF.

Graham

 

[Warren Weber]

"Warren Weber" <hiview@bresnan.net> wrote in message
news:adWdnchJmN3chM_anZ2dnUVZ_vKunZ2d@bresnan.com...

Just thought about this today. How do I figure the instantaneous watt
power available from a charged capacitor, Have been in electronics and
repair since 1943. But this thought never occured to me. As a Charged
1000mfd with 12 volts would be. And them I assume a 4000 mfd would have 4
times the watts available. Any ideas on this? Warren
--

Thanks for the replies. I am not too old to still learn. Lots of good info
one these sites and great that so many people help each other. Warren