I'm trying to get a better understanding of how this 1.5v pulsing transmitter works. I found it on Youtube and modeled it up with some success. https://www.youtube.com/watch?v=aLS9DsF2ilg The schematic is as such.
My questions are: 1. Does the LC tank circuit need to be tuned to the crystal freq? When I insert a 40Mhz crystal I can see it on the spectrum analyzer but tuning the tank circuit capacitor doesn't seem to effect anything.
In the video the guy mentions moving the tank capacitor to ground instead of the power rail? Any ideas?
How does the pulsing action work? Is it a side effect of 1.5v, the 220k resistor and the NPN choice?
Lastly, when I insert a 10nf cap across V+ and V- the oscillation stops.
Thanks in advance to anyone who has ideas on this.