Eight Henry inductors from an old “tube” radio receiver

in Teardowns by DP | 2 comments

Kenneth takes apart a few old “tube” radio receivers and finds 8 Henry inductors inside, which is several orders of magnitude more then regular inductors we’re accustom to. He proceeds to hook it up to a 10 uF capacitor, and tests the ringing frequency of this LC circuit.

This LC pair resonates at 12Hz, which is crazy. Usually, getting an LC circuit to even resonate as low as audio frequencies is challenging, but here we’ve got one which resonates at infrasonic frequencies, and with plenty of arcie-sparkie to go with it.

Moral: Always dig through e-waste piles, and make sure you always have a friend with a pickup truck.

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Comments

  1. Just be aware that many old capacitors and inductors contain PCBs (Polychlorinated biphenyl).

  2. jbeale says:

    I was just going to post that some killjoy will probably warn you about PCBs in the oil-filled capacitor. But I see I was too late! In the same vein as this, I recall a demo in my freshman physics class of a 1-H inductor with a 1-F capacitor (both huge, I couldn’t have lifted either one) and it really did resonate with a period of 2*pi seconds.

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