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Thierrys theremin (pitch only) modified
Started By: Leon Pijpers
Last Updated: 3759 days ago
In this video the first working prototype of my theremin (pitch control only, no volume control yet) is shown. On the tek scope the yellow trace is the output of the fixed oscillator, and the green one of the variable sinewave oscillator, both running at about 540 kHz. The blue trace is the difference wave form, which can be heard on the pc speaker. For first test it is connected to the mic input. This Theremin is a modified : http://thereminworld.com/Forums/T/29231/my-new-year-gift-to-tw 2N5484 was not available, so 2N4393 (about €3) is used, because i still have some stock of these oldies. For making a new theremin, better use the MMBFJ309LT1G because it is €0.58. The coil value 1mH was not available, so i used 330uH. Using LTspice (available from www.linear.com for free!) I simulated the circuit, adding 100pF across the coil to get a better sinewave, less distortion. Because the coil value was smaller, I had to increase some capacitor values. in the following video the working prototype is tested and the waveforms checked on an oscilloscope. http://www.youtube.com/watch?v=V4RE-C5VJNs