[sdiy] NPN/PNP matching for expo converter

[aankrom]

NTE sells a few matched NPN/PNP pairs and they do it by hFE within 10%. 
Just need to figure out whether the cost vs. time sorting through my 
stash of 2N3904's & 2N3906's is more appealing. I like playing with the 
hFE tester on my DMM so I'll probably do that.
An expo. converter for a phaser is less critical than for an audio VCO 
anyway.

AA

On Wed, 18 Apr 2012 12:25:28 +0100, Tom Wiltshire wrote:
> There's tons of stuff on transistor matching in the archive:
>
> http://search.retrosynth.com/synth-diy/
>
> Whether you match for Vbe or hFE depends on the circuit. I couldn't
> tell you for the Maestro phaser.
>
> HTH,
> Tom
>
>
> On 18 Apr 2012, at 03:18, aankrom wrote:
>
>> I'm considering building one of the Maestro phasers and noticed that 
>> each one has a 2N3904/2N3906 that are "matched." When matching NPN to 
>> PNP are you going for close hFE's?
>>
>> AA
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