Hi All
I have made some minor changes to a circuit I found on the web. What I wanted to try was to modify the capacitance of the tuned circuit by using a red LED. Apparently in reverse biased mode, a LED exhibits a certain amount of capacitance.
Now when I switch on the circuit, all I hear is a very faint 'rushing' noise like the circuit is not oscillating. Seems like the LED is causing an open circuit. When I short the LED legs with a wire, then I get the healthy rushing noise like its oscillating. Do you know whats wrong with this circuit.
I have also connected a 1meg Ohm resistor b/w the top of the LED and the center leg of the 1k ohm new potentiometer.
BTW the zener i used was 5.6v not 7.5 if that matters.
Thanks all
Shelton.
I have made some minor changes to a circuit I found on the web. What I wanted to try was to modify the capacitance of the tuned circuit by using a red LED. Apparently in reverse biased mode, a LED exhibits a certain amount of capacitance.
Now when I switch on the circuit, all I hear is a very faint 'rushing' noise like the circuit is not oscillating. Seems like the LED is causing an open circuit. When I short the LED legs with a wire, then I get the healthy rushing noise like its oscillating. Do you know whats wrong with this circuit.
I have also connected a 1meg Ohm resistor b/w the top of the LED and the center leg of the 1k ohm new potentiometer.
BTW the zener i used was 5.6v not 7.5 if that matters.
Thanks all
Shelton.