I want crystal radio that is not needed with variable capacitor. Please show me their connections and diagram.

Question

Show mw the drawing because I needed it in my exhibit.

Answer 1

I can't show you the diagram here as this is text only. But, remember, your tuning circuit is a combination of inductance (coil) and capacitance. Together, they form a resonance.

It really doesn't matter, in this application, which one you vary. You can vary the capacitance (as normally done) or you could vary the inductance.

Use the same schematic as your regular one, but try this:

Wind the coil on PVC tubing using enamel wires. (magnet wire) Then, strip off the enamel from the ename wire by running (carefully) sand paper back and forth so that a thin strip of bare wire shows on very narrow strip along the PVC tubing. If you do this carefully, you can keep the wire from touching, but still strip enough to make contact.

Then, rig your setup so that a copper wire can slide over the bare portion of the coil. This copper wire will be your tuning mechanism.

I'll suggest starting from using 1" PVC tubing, 150 turns of enamel wire, and capacitor of 150pf or so.

When you connect one side of your coil and the slider to your capacitor (fixed), you form a tuning circuit.

Rest of the circuit stays exactly the same.

Answer 2

even for crystal radio, a commercial capacitor is used as it make tuning easier. you can wind your own coil, that is not so critical. the problem with home built caps is it is not easy to get a high capacitance value needed to tune in the AM broadcast band. You can use the 2-sided printed circuit board to make a fixed cap but then you will have to make the coil tunable, a much more difficult chore, that is how the "Boy Scout" kits worked when i was a kid, and they weren't very satisfactory. And you will still have to make the hour drive to get the PCB material. if you live a hour from a major city, it is possible that there won't be a local AM station that can be received by a crystal detector either. crystal sets are not for weak signals.

Answer 3

hey buddy, try that translator again