[sdiy] current mirror for NPN expo?

[dan snazelle]

that is how i ended up trying it...however the pitch is not exactly the same on the second core...even though the part values are the same...i will keep working at it

thanks




On Sep 19, 2011, at 12:15 PM, David G Dixon wrote:

>> can anyone point me towards info on how to use ONE NPN EXPO 
>> to drive two vcos?
> 
> Can't you just mirror the current-sourcing one?  I.e., tie its emitter to
> the other two, and connect its base to the other current-sourcing one?  You
> should be able to replicate the current as many times as you want this way.
> I did it with five transistors in a four-pole filter once; it worked a
> treat.
> 
>