Tuesday, October 30, 2012

MW_Regen_1V_One Triode Pentode Tube_8JV8

Signals from the antenna (a 2-meter piece of wire) are fed to the input tank via C3. Antenna coil LA was wound on a piece of 19mm diameter plastic tubing (in this case it came from a junked clothes hanger). There's a tap at 25 turns from the cold end.

The triode section works as a regenerative detector, being biased by C6 and R8. It's grid and cathode share the same DC voltage and regeneration is controlled by varying the plate voltage. Detected audio, taken from the plate, is first run through the low pass filter R4 and C4 and then fed to the pentode's grid. The pentode part is biased by C8 and R9. R6 and C7 provide power to the second grid. Finally, T1 matches the low impedance of the small speaker to the fairly high output impedance of the tube. For simplicity's sake there is no volume control or power switch.

Source: http://coolshop.dnsalias.org/projects/1tuberegen/1tregenrx.html

No comments: