Crystal Radio Receivers depend on the 1N34A Germanium Diode’s rated Forward Voltage Drop ( The amount of voltage before is starts to conduct ) of .3 volts. Silicon diodes are rated around .7 volts. However, the voltage for the 1N34A Diode is measured with a current around 10ma. As the current increases so does the Voltage Drop and vise versa. The 1N34A Germanium Diode actually starts to conduct at very low voltages. The 1N34A will start to conduct around .1 volt. So in a Crystal Radio Receiver you need only to produce around .1 volt from your Crystal Radio Set to begin to hear a station. That is the reason the 1N34A Diode is so popular with Crystal Radio Set Builders.
The 1N34A Germanium Diode, a ceramic earphone and a tuning coil are all that is needed to make a simple crystal radio set.
Because Crystal Radio Sets use only the power coming from the antenna, a good antenna is required to drive the earphone of a Crystal Radio Set. If you live in the city close to a transmitter antenna then you should be able to pick up that station on your Crystal Radio Set ( Xtal Radio Set ) with only a short antenna wire.
1N34A Germanium Diodes are some times called Crystal Diodes. And sometimes referred to as IN34A Diodes or Germanium Detector Diodes. And thus the name Crystal Diode Radio Sets is used by some instead of Crystal Radio sets.
The 1N34A Germanium Diode is an improved version of the 1N34 diode. So any circuit that specifies a 1N34 Germanium Diode can be replaced with the 1N34A Germanium Diode.
1N34A Diodes are used in may other circuits besides Crystal Radio Sets. Because of their low forward voltage drop, they have found uses in Sound Effect Circuits and Voltage Dropping Circuits. However the use of the 1N34A in Crystal Radio Sets are of the most common uses I know of. The 1N34A Germanium Diode is the one supplied in my Simple Crystal Radio Kits.
The 1N34A Germanium Diode is no longer made in the United States to my knowledge. There are only about three manufactures of the 1N34A Germanium Diode that I know of World Wide. The 1N34A Diodes I sell are of highest quality. I have sold 1000’s 1N34A Diodes and not one bad 1N34A that I know of. You can Buy 1N34A Diodes from me with confidence.
The 1N34A also is very popular in Ham Radio and Amateur Radio circuits. They are used as detectors and in up converter and down converter circuits ( Mixers ). The 1N34A is also a good RF input bypass or shunt to protect equipment from voltage spikes.
The 1N34A is also very popular in sound effect circuits acting as a clipper to produce Fuzzy sounds and various distortions. Guitar sound effect circuits and Pedal circuits often specify these.
Some places are selling silicon diodes as a substitute or equivalent replacement with the 1N34A number as germanium. Some of there data sheets even say germanium in the header but state silicon in the data area. Mine are germanium point contact diodes and not Schottky Silicon Diode.
I have a large supply of other types of Germanium Diodes other than the 1N34A . These included the 1N60 Germanium Diodes, 1N270 Germanium Diodes, 1N277 Germanium Diodes. Next to the 1N34A in popularity with Crystal Radio Set builders is the 1N60 Diode. The other diodes ( 1N270 Diode, 1N277 Diode ) can be used in Crystal Radio Sets ( Xtal Radio Sets ) but are not used as much as the 1N34A .