[GreenKeys] Distortion problems

[Jeffrey D Angus]

On 7/6/2015 4:04 PM, Brooke Clarke wrote:
> Don't forget that the time constant of an L-R circuit is L/R, unlike a C-R
> circuit where it's C * R. So to get faster response in an L-R circuit you
> need to ADD series resistance.
> So even if a 5 Volt signal can pull in an electromagnet the speed of
> operation will be very slow. If you go to a 50 Volt signal and add
> resistance to get the same pull in current the action will be much faster.
In the overall scheme of things, to change the voltage across a capacitor,
it's take a HARD voltage source, with an unlimited current to push
electrons into the capacitor fast enough.
The opposite is true with an inductor. It takes a hard current source with
an unlimited voltage (compliance) to make a fast change across the
inductance.

A 120 vdc source, with a 2K ohm resistor to limit the current to 60 mA
is actually a "poor mans" current source, with a compliance of 120 volts.

You can actually how this all works with LTSipce Using a square wave
source and upping the voltage and series resistance and watching the
rise time across the inductor.



-- 
Jeff-1.0
wa6fwi
http://www.foxsmercantile.com