donbosco: Dom Bosco Mosquito Injector

My example was not functioning and I decided to dismantle the probe to understand its function and design.

The dismantle process can only be done in a destructive manner but yielded useful information as follows:

The device is essentially composed of a non blocking oscillator comprising only a pulse transformer with two windings, a PNP transistor (2N408) and a capacitor of value around 500pf.  The precise value was not readable as the capacitor appears to have been damaged (probably by connection to a high voltage equipment under test).

The circuit appears very similar to the Eico injector of a similar vintage (details on antiqueradios.com).

 

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