A Single Transistor Harmonic GeneratorAuthor: R.J.Edwards G4FGQ © 13th March 2004
A sinewave drives the transistor via a coupling capacitor and resistor. The transistor operating angle is set by input amplitude and resistor value. The collector load is either a resistor or an LC circuit tuned to a particular harmonic.
The working tuned-circuit Q is assumed to be 30. The reactances of L and C are 200 ohms. Link-coupling can be used to take an RF output from the tuned circuit coil. Small operating angles are obtained with high values of base resistor. The driving voltage is optimum when operating near the transistor reverse Veb rating.
It will be noticed with small operating angles that the output amplitude falls off slowly and smoothly with increasing harmonic number. Whereas with larger operating angles some harmonics may almost disappear from the sequence. This conforms to Fourier. The output amplitude of lower frequency harmonics increases with larger operating angles and greater DC collector current until transistor saturation occurs.
The computed data is only approximate. This is due to the transistor being used in a non-linear fashion. Choose a transistor with a high Ft and low capacitance for best results.
Run this Program from the Web or Download and Run
it from Your Computer
This program is self-contained and ready to use. It does not require installation. Click this link Harm_Gen then click Open to run from the web or Save to save the program to your hard drive. If you save it to your hard drive, double-click the file name from Windows Explorer (Right-click Start then left-click Explore to start Windows Explorer) and it will run.
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