Re: variable resistances (Re: [sdiy] Multi-Input filters)

[Roman]

there's even a parameter specified for zeners, called dynamic 
resistance, that says what resistor would be connected to ideal 
brickwall zener to have response like real zener. And it changes with 
current. Personally I'd pick small zeners from 2V7 - 3V6 range. They 
have smoother knee, and should be easier to use.
Add some caps, drive it with variable current and you have zener 
filter!

Roman


benno <benj at iinet.net.au>:

>on that note, i had the thought that the reverse breakdown of a 
zener diode
>would behave more like a current controlled resistor than a normal 
diode
>would.
>
>or am i more full of shit than harry?
>
>B
>
>on 11/2/03 12:32 PM, harrybissell at harrybissell at prodigy.net wrote:
>
>> This IS the case for all the diode type transconductors where we 
vary
>> standing current
>> and voltage changes only slightly. I presume my explanation 
expands on this
>> idea... or I'm
>> full of sh!t. whaddya think ???
>> 
>> H^) harry
>
>