Voltage-Controlled Capacitor Spice Model now on my website

I don't have time to play with this just now, but one quick question:

Given that C is a variable capacitor, set C to 1F and charge it to 1 volt. Now change C to 0.5F. What is the new voltage?

--

John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com

How many 1 farad capacitors are you aware of?

Oh and would not a 1F charged cap dump into a 0.5F cap and fully charge it? If that answer is yes, then the voltage would be the same... slightly less even, all elements considered.

You thought it would morph the EMF into something else?

In LT Spice, you can use any C value. 1F is the generic capacitor. I usually normalize theoretical circuits to 1F, 1H, 1 ohm. [1]

In real life, Digikey will sell you 1F caps. Or 5000F caps. But not variable 1F caps.

I'd like to know if Jim's model conserves charge, or conserves energy, or conserves voltage. Or whatever it does.

[1] I do find myself picking standard values, like 39nF instead of 40 nF, and worrying about leakage and stray capacitance and power dissipation, when none of these matter in Spice.

--

John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com

I haven't tried that. Since it _is_ a capacitor, it'll depend on whether a simulator treats capacitors as charge-controlled devices or otherwise. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

Voltage-Controlled Resistor Spice Model Updated

See VVR.zip on the Device Models & Subcircuits Page of my website

Includes Library File (.LIB), LTspice Symbol (.ASY), PSpice Symbol (.SYM)and a JPEG showing how it was developed. ...Jim Thompson

-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at

| 1962 | I love to cook with wine. Sometimes I even put it in the food.

I've seen maybe 10 or 20 examples for sale retail. seen adverts for more.

"change", not "charge"

conservation of matter and all that.

--
umop apisdn