Most basic crystal radio and how they work

The volume is pretty low so you'll have to turn it up to hear clearly.

Apologies for filming at twilight, hope it doesn't affect the viewability too much.

[gavinnorthants]

I made one of these at School. Everyone was trying to guess how many turns to pick up stations. For some reason, I just thought I would keep wrapping the wire around the core until I heard a radio station. Once I did I had a tune around to make sure the radio was tuned in to the best area of the medium wave band, so I could pick up my favourite radio stations. Just cut off any excess wire and solder the coil in. Everyone seemed surprised but to me just seemed common sense!

[kensmith]

The real reason for the diode is because we can't hear 1MHz. The diode converts the 1MHz at some amplitude into a voltage proportional to the amplitude by working as a sort of electrical "check valve" If the 1MHz was swinging from +1V to -1V, only the +1V part would go through the diode.
It will work a little better with about a 47K resistor in parallel with the earphone. The circuit as you have it relies on leakage current to let the voltage on the earphone go back towards zero.

[tobiasgertz]

The fact that your radio use being overloaded by a strong local station isn't exactly due to your "dodgey" construction techniques. It's been a problem for all radios since the beginning. Giving your antenna a more directional pattern is one of the first steps in avoiding this problem. Good work mate.

[sun-pg]

Made on of those years ago for my son.

[Bob_Suruncle]

Was hoping for a part number or specs on the diode.

[nothing-mmui]

can you get the coil from a regular radio as well?

[YusupYusup-ezqn]

I make it work but always have to use mini amp if don't I can't hear anything

[OMNI_INFINITY]

Tuning capacitor means it’s NOT the simplest

[samconomo]

Are you Australian oi oi oi, just joking.
Thanks for the great video.i am gunna try an build one with my grandson.
Sam.