G3ZJO just posted a nice little blog entry about the use of LEDs (which are nearly ubiquitous) as varicaps (which are often harder to find). Lots of people are using these in their QRSS beacons, no doubt in part to the work of Hans Summer which was the first person to bring them to my attention. Someday, I’ll begin to work on electronics again, and I’ll make use of this information.
pretty neat stuff. Wonder if its possible to make a very small FM receiver using this technique to control the oscillation frequency of a negative resistance circuit using the J310 and BC212 ?
the plan here is to run it in forward bias mode to reduce the voltage swing needed for a useful capacitance change.