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| Joined: | Dec 12th, 2007 |
| Location: | Dunedin, Florida USA |
| Posts: | 38 |
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The biasing is similar to what you would do for a transistor, a simple voltage divider. (Note: This will not work with the 500 uH coil in the circuit.)
I added a 1.5 volt battery and connected a 15k resistor to the (+) battery lead and a 10k resistor to the (-) battery lead and circuit ground. Then I soldered the two remaining resistor leads together to form a voltage divider. This resistor junction is then soldered to the junction of the antenna - diode input lead. This puts about 0.55 volts through the diode to ground. That is well into the conduction zone of the germanium diode. I sized the resistors to minimize current and provide long battery life.
The slope of the conduction zone current is pretty steep, so that adds a little amplification to the antenna signal.
Bruce