[ARC5] Reverse engineeing the BC 456

[Bruce Long]

Add an emitter follower.  Output impedance is approx.  26/ Ie(ma)   Ohms  


      From: J Mcvey via ARC5 <arc5 at mailman.qth.net>
 To: "ARC5 at mailman.qth.net" <ARC5 at mailman.qth.net> 
 Sent: Saturday, March 18, 2017 2:04 PM
 Subject: [ARC5] Reverse engineeing the BC 456
   
My idea to to modulate the bc456 with a 'level shifted" electret mike hit a snag.
The mike input transformer has ratio of 1:10 primary to secondary which is terminated with about 3000 ohms which means that the primary is looking to match a 30 ohm device?
That explains why the modulation is so poor. My T-17 likes to be around 2K.It also precludes using the electret output directly because the internal fet needs a drain resistor of 2- 5k to provide the gain, requiring a medium Z to match.Bummer...Nothing is ever simple...
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