Electronics > Beginners
Crystal Radio Breadboard - Zero Sound
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t1d:
I breadboarded this circuit. I have zero sound, not even background sizzle.

- All components are of decent grade and proofed. Most came from a Crystal Radio parts house. I understand that a new earphone can be "jammed," but this one is sounding on a known source.

- All connections have proven connectivity, point-to-point.

- The ground is solid and is to Earth.

- The antenna is double strand zip cord of long length, maybe 50+ feet. However, I have not strung it out; it is still on the spool. Each strand is soldered in parallel. This should give good volume.

- The diode is germanium; 1N34A.

- There are local stations.

- I am using a 0-335pF variable capacitor; Pin #1 and GND. Data Sheet Attached. It operates CCW, but this is of no operational consequence.

- I have varied the direction of the diode with no improvement.

- I did not have a 0.001uF smoothing cap, so I used a 0.01uF cap. I have removed it from the circuit, with no improvement.

I have reviewed the circuit and, if there is an error, I just can't see it. So, your help, please and thank you.



Photon939:
What earphone are you using?

A crystal radio is supposed to use a crystal earphone (piezo or similar?) they are very high impedance which is required to run from a crystal radio.

A regular 16 ohm magnetic voice coil headphone will probably just short out the crystal radio and result in no audio.
t1d:

--- Quote from: Photon939 on December 19, 2018, 04:29:42 pm ---What earphone are you using?

A crystal radio is supposed to use a crystal earphone (piezo or similar?) they are very high impedance which is required to run from a crystal radio.

A regular 16 ohm magnetic voice coil headphone will probably just short out the crystal radio and result in no audio.

--- End quote ---
Thank you for your help. The earphone is of the proper type that you specify and it came from a Crystal Radio parts supplier. It is very sensitive and hurt my ear on testing.
alanb:
A few things to check:-
1- Are your local stations AM
2- Is the resonant frequency of your circuit in their range use formula f= 1 /(2pi sqroot(LC))
3 - the loading of the earphone and parallel cap may be too great for the circuit. Are you using high impendence earphones? Reduce or remove C1

Good luck.
alanb:
I notice that you say your antenna is still on the spool. You should unwind it and get it outside.
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