Horrifying Transmitter PA

I can only dream about achieving that standard of build quality. :(

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Yikes. A complete bastard mixture of righteous dead-bug and effete Manhattan construction.

Cheers

Phil Hobbs

I thought he was talking about using 7805 voltage regulators as the output stage. You can (ab)use those lots of ways...

I was. I wonder what the Ft of a 78L05 is?

Probably not that shabby when it's being used as a power buffer, with the signal coming in the "ref" pin, as it is here. The expectation is that the feedback loop is going to be rejecting voltage ripple on the Vin terminal so the voltage gain is higher and bandwidth lower from that way.

It's only a two-stage amp internally, diff pair feeding an emitter follower, and I think feeding it via the ref pin drops the Miller comp cap out of the picture as both diff pair inputs are moving in unison.

Driven that way I think the whole IC functions more or less as the equivalent of a common base amp feeding common emitter power buffer, but one you don't have to think about biasing n shit.

Common collector/emitter follower, rather

I dare not share my monstrosities.

GH

On a sunny day (Tue, 14 May 2019 08:01:27 +1000) it happened Clifford Heath wrote in :

Interesting, making things from parts that you have. Did not expect the 7805 series to go to MHz ..

Something for when you are stuck in 'merrica and need to send an SOS and only have some old power supplies.

looks metric to me.