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Title: SiC rectifiers as high-level varactors? Post by: Opcom on July 07, 2008, 03:33:10 PM Was just looking at this datasheet for an 10A 600V SiC (silicon carbide) rectifier. What caught my eye was the "Figure 4. Junction capacitance versus
reverse voltage applied" on page 3. 50 to 450 pF for 200 to 1 volts. I dunno that's got to be good for something. Tuning?? Title: Re: SiC rectifiers as high-level varactors? Post by: W1EUJ on July 07, 2008, 04:30:37 PM All diodes have capacitance that varies with reverse voltage. The reverse voltage changes the width of the depletion region, changing the distance d in the capacitor equation C= eA/d. AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
Varactors are designed to exploit this effect; most other diodes are designed to minimize the effect. There have been a couple ARRL Handbook circuit using non-varactor diodes for this purpose. A varactor diode built for multiplier use is what you might be thinking of. David Goncalves |