big L

In my early days as a budding electronics person, I played with a television set that did that. The same tubes amplified the video IF and the audio.

I also recall cheap toy walkie-talkies from the 1970s that used a single transistor as both a super-regenerative receiver and as a transmit oscillator.

In another thread just these last few days, Cursitor Doom showed us a 1970s era Grundig radio that used the same transistors for the 10.7MHz FM IF and the 460kHz AM IF.

I those days, transistors were expensive. Coils and switches were cheap.

Jeroen Belleman

I have a wall wart here with a 0.6VA transformer in it. It's built for

If it's saturating at 240V I'll be under-estimating the inductance.

If I were to pull it apart and replace the secondary with a copy of its primary. connected in series that'd be 600H in about the size of a golf-ball.

And the reverse situation a bit later on. "Nine Transitor Radio" models proudly boasting 'lots' of devices where at least one of them wasn't even connected!

link not valid from here . . . .

I only ever did commercially impractical valve circuits. Often using one-off components that couldn't be replaced without major toil.

One way of separating the hobby from work.

RL

My apologies, it should have been:

(Pleae note, it is "http" not "https".)

When I was in high schoolI worked summers in a physics lab at a university.

I designed a radiation counter, for class use, with tubes. It used six of the cool dekatron gas-filled tubes that were decade dividers and displays in one bulb.

It depends on the load on the secondary.

In normal operation the energy is transferred from the primary transformer winding to the secondary but if the secondary is open circuit then the primary behaves just like any other inductor and stores energy in the magnetic field.

Things go bad very quickly if the soft magnetic core ever saturates.