I know that PN junction diodes are not used in RF mixers as they burn out due to high heat emission, for this Schottky diodes are used.
I am working on a project where I will be producing an IF of about 11 MHz from an RF of about 400 MHz. Then I will feed the 11 MHz IF after proper amplification into a PN junction diode and a red LED in series so that the LED turns on whenever there is sufficient IF power, signifying detection of a signal presence.
The LED should as usual stay lit up due to the high portions of the IF signal and in the low portions stay reverse biased. To keep the current within limits of the LED I will ensure the required resistance.
Is there any possibility of the LED and the PN junction diode burning out at 11 MHz?
Some other questions.
- Why does the PN junction diode burn at RF frequencies (well within VHF and upwards?)
- Up to what frequencies can a PN junction diode and an LED (keeping in mind the various colors) work fine without burning?