Mini audio transformer, where are you?

[Makaram]

this is an old radio which I was told should contain a mini audio transformer but I don't see it! is it there?

 

[ronsimpson]

You should not believe everything you are told.

 

[ronv]

Don't see one. It may have a large capacitor to the speaker and not a transformer.

 

[JimB]

this is an old radio

But it is not old enough, you need something from before about 1970.

JimB

 

[Makaram]

ahhh k thanks guys

 

[audioguru]

I got a portable transistor radio as a gift in about 1958 that used audio transformer.

Here is the schematic of a 1955 Philips audio amplifier that used an expensive mini output transformer but they avoided using an expensive mini driver transformer:

 

[JimB]

A trip down memory lane there AG.

I think there is a mistake in that schematic, the OC71 is a PNP transistor, the power rail at the top of the schematic should be the -ve rail.

In a PNP, the collector is negative with respect to the emitter.

JimB

 

[audioguru]

I think there is a mistake in that schematic, the OC71 is a PNP transistor, the power rail at the top of the schematic should be the -ve rail.

In a PNP, the collector is negative with respect to the emitter.

JimB

I agree that in 1955 Philips got the polarity of the battery wrong.