[sdiy] TomG's 9v diode ladder VCF

[Doug Tymofichuk]

Here is a circuit for matching diodes, much better than 
just using your diode test range on your meter:

http://www.angelfire.com/electronic/epeasant/circuits/diodemch.gif

On Thu, 12 Apr 2001 16:30:17 GMT Plutonique9 
<Plutonique9 at symbiocom.com> wrote:

> Hey there people,
> I'm going to build the 9v diode ladder from the Cookbook as 
> my introduction in VCF construction. I have a couple of Q's 
> regarding it though.
> 
> Diode matching:: I'll be using 1n4148's for the diode 
> ladder, I'm pretty sure these need to be well matched. On 
> my multimeter, it has some sought of diode testing inbuilt, 
> this is a radioshack digital multimeter BTW. Is this 
> suffiecient to match diodes, or should i build a dedicated 
> "diode matching" circuit, which runs a 9volt battery 
> through the diode via a resistor, no difference?
> 
> Also, using a LM394 should yield better results than two 
> 2n3904's, right, $4.00 here, hope its worth it.
> 
> Also, I'm not sure where that "BIAS" circuit is supposed to 
> link up to? At the input, it has a symbol, there are 4 
> other positions on the schematic which also has these 
> symbols, does the "BIAS" go to all of these?
> For example, what does the 100k resistor going into the 
> non-inverting input of the TL071 connect to?
> 
> Hmmm, I think that covers all the shady areas, thank you 
> for any insight.
> 
> 
> -- Plutonique9, Plutonique9 at symbiocom.com
> 
> http://www.mp3.com/Plutonique9 
> 

----------------------
Doug Tymofichuk
dougt at cancerboard.ab.ca