I am Trying to make a training tool that lights up when a radio is transmitting a few inches away from the antenna. The circuit works great on my bread board, but as soon as I transfer it to a pref board it does not work. I have tested the circuit and I have good connections at all points. I used my Precision Variable DC Power Supply to apply 1.8V and it lights up just fine across the circuit. Any advice now to make this work? basic skill level here, but lots of resources available. Thank you.


simulate this circuit – Schematic created using CircuitLab enter image description here

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    \$\begingroup\$ The only way this circuit can work is if there is a significant amount of capacitance between the non-antenna node and ground. The breadboard provides this capacitance, but your perfboard implementation does not. \$\endgroup\$ – Dave Tweed Dec 9 '16 at 11:32

Pluggable breadboards have some capacitance between nodes. The perf board will have substantially less of this internode capacitance. Maybe you need to experiment with the perf board and some small valued capacitors.

You will have to do your own research regarding the amount of capacitance the breadboard has. I have not measured how much it is but just know it exists because how it can change circuit behavior.


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