Audion receiver, more sensitive than the crystal envelope detector.
In this case the operating point of the transistor isn't on the linear section, but on the exponential part. As you can see in the next picture, its operation is similar to the diode:
- the transistor conducts the current in the positive period
- the transistor "not" (to a small extent.) conducts in the negative period.
(it's a FET, but it works the same as the BJT.)
It's the simulatio in LTSpiceXVII, the name of file is: audion-receiver.asc
The physical circuit on the test-board:
The frequency of carrier is 545kHz, the modulator frequency is 5kHz and the modulation depth is 70%.
The circuit can modulate a lower voltage than the forward voltage of the diode. In this case the peak voltage is ca. 80mV. Goodbye 2024.
Distributed under the MIT License. See LICENSE.txt for more information.
Varga Laszlo - https://vargalaszlo.com - [email protected]
Project Link: https://github.com/vargalaszlo87/audion-receiver
