View single post by Jan
 Posted: Oct 25th, 2016 07:09 PM
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Jan

 

Joined: Jun 5th, 2012
Location: Inverness, Scotland
Posts: 85
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 I thought the circuit was upside-down, then realised they are PNP transistors and +ve is at the bottom!

There appear to be some errors in the design as shown.

D1 zener is shorted by the BE junction of T2.
(D1 has no voltage associated with it anyway)
P3 will do nothing because there is a DC block C9.
Looks like an unnecessarily complicated tuned circuit at the input. No values given for L1/L2.
No transistor types.
Zener D2 no voltage given


Reverse image search gives transistors as:
T1-KT3107 BC556 ew. BC212 (PNP)
T2-KT3102 BC547 (NPN)
T3-KT3107 BC556 ew. BC212 (PNP)

Looking carefully, zener D1 is probably used a noise diode.

Looks like some very noisy radio receiver with the sort of noise where you can imagine you can hear voices mixed with any radio signals.

Are the dual tuned circuits supposed to be some scalar-wave stuff?

Last edited on Oct 25th, 2016 07:15 PM by Jan