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Strona 12 z 46


Spy Circuits

- 5v for maximum output.

The Voyager has been copied by many kit-makers but nonę has surpassed its performance. Here is a "knock-off1 of our older design. It is mounted fiat on a 9v battery:


Here are 2 morę two-transistor circuits using a 9v supply. We have also included the technical limitations of th

DAVID'S DESIGN:


Faults with this Circuit:

1.    Very Iow microphone load resistor.

2.    4u7 not needed from microphone. 22n is sufficient.

3.    3p3 is very Iow for BC 547. May need to be higher. - 10p preferred.

4.    Bridge biasing of audio stage is not needed. Simple biasing is adequate.

5.    Base biasing of oscillator is very wasteful in current.

6.    22n is very high for base bias of oscillator - restricts incoming audio.

A BIRD'S NEST DESIGN

2011-12-08


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