Circuit thing

Does Veeky Forums know what this thing is? I found it at a garage sale and bought it because it looked interesting.

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en.wikipedia.org/wiki/Foxhole_radio
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theremin

anal thermometer set. you put the tube i ur ass and plug it into the outlet.

The wire on the right that connects to the glass tube. How exactly does it connect to the tube? Does it go inside the tube, or does it wrap around the tube? Is it a continuation of the wire on the left side that coils around the tube?

Can you show us another photo that shows a close-up of the tube? Preferably a side view. I want to see what the wire on the right connects to.

Also, if you look closely at the right end of the tube, you can see a little shiny sphere. Is that a bead of mercury? What is that?

The wire is wrapped around the tube, the tube is empty as far as I can tell. I don't know if there is some kind of gas in there or not.

Looks like a crystal radio.

looks like maybe a electromagnetics demo thing? i don't know what the toothed thing could be. maybe a spark gap?

I assume that the glass tube thing is a vapor lamp that's powered by induction.
The switch could be part of a start circuit. I guess.

But I'm not really sure.

>spark gap
Could be. But why the mercury/molten metal?

It's purpose is to remove BPH.

What the hell is that toothed thing?
Is it limiting the voltage differential by inducing sparks?

That's my guess as well, but it doesn't look like there's any way to tune it.

OP here, there is no metal in the tube. It is just the reflection of the ceiling light on the rounded end of the tube.

lightning detector?
knob on edge is connection to aerial and thumbscrew connection near switch is for ground.
Tube is probably filled with low pressure noble gas.

Is that switch like a sliding switch or like a morse-type press-down switch?

Is there a way I can test that without opening the tube, like running a current through it?

that sounds very plausible but why the switch?

It slides back and forth

got a high voltage source?

switch is a safety to ground the aerial, ti shorts the whole thing, both the coil on the tube and the spark gap.

The best I can do is a 9V battery, I don't know what else I could use.

radio i guess.

vanDegraf generator
spark coil
radio transmitter
tesla coil
neon sign transformer
microwave oven transformer

Thats what we call in the industry an "inductor."

I don't think I have any of that laying around

en.wikipedia.org/wiki/Foxhole_radio

Why would somthing age faster due to photograpic data?

What, Amerika eating baby Indians with India?

nice jeb

It looks like some kind of classroom RF demonstration thing.
The toothed sheet metal parts would act as a capacitor, and the switch would enable or disable the ability of the circuit to resonate.
There is probably a noble gas in the tube that lights up when excited by RF.

Simple resonating circuit.
Antenna picks up RF electromagnetic field, if [math]f \approx {{1}\over{2 \pi \sqrt{L C}}}[/math] the (alternating) current through the inductor will be maximal, it'll induce an electric field inside the glass tube and something inside it will happen. Probably filled with a noble gas so it lights up with the E field inside; your eyes act as an optical low pass filter so you basically demodulate the AM signal and "see" the unmodulated signal (possibly audio). Loud sound -> bright light.

The switch shorts the capacitor and inductor so the voltage across them is zero and nothing happens*.

So basically these
* Might not apply if frequency is high enough so that [math]\lambda = {c_0 \over f}[/math] is on the order of the length of the wires.