Just a single transistor sinewave generator circuit can easily be employed to generate a simple phase shift oscillator.
The output is a sinewave having a 'lump' within it, meaning that the distortion content is pretty higher, around 10%.
This is simply not usually a difficulty, frequently while producing sound tones a higher harmonic content could make a much more appealing sound.
The sine wave purity could be enhanced through placing adjustable resistor (25 ohms) in the emitter lead of Q1 (x).
The resistor is modified to ensure that the single transistor sinewave generator circuit is merely only oscillating, then the sinewave is comparatively natural.
Nevertheless, in case the power supply level differs, the oscillation might stop completely.
The functioning frequency could possibly be diverse by placing 10k variable resistor in series along with R3, or by altering C1,2, 3.
Generating C1,2,3 similar to 100nF will certainly possess the performing frequency.
Furthermore As well, the operating frequency could be voltage managed with a FET in series with R3, or optically operated by an LDR in series with R3.
VLF Sine Generator Circuit
Creating extremely low frequency sine waves (i.e. lower than 0.1 Hz) provides numerous troubles.
Timing capacitors normally have to be big value electroytics, any sort of amplifier utilized needs to be D.C. combined, and also the amplifier's input impedance needs to be quite high.
One regular technique is to very first create low frequency square waves, after which to shape most of these directly into an approximation of a sine wave by using a number of non linear devices, like diodes.
The VLF sine generator circuit demonstrated in Fig. 1 is a reasonably easy technique depending on the well known Wien bridge.
An n channel FET and a PNP transistor are usually organized in a DC paired circuit and the voltage gain is dependent upon the negative feedback R3 and R4.
The gain require simply be around three, hence in case the bias needed by the FET is 3V the output level will likely be around half the supply voltage.
Due to the fact R1 could be a high value resistor the value of the capacitor is merely 1 u5 for sine wave outputs of 0.01 Hz.
This capacitor can be found in polycarbonate. The amplitude of the output could be altered through RV1 to provide low harmonic distortion and also to be around 10V peak to peak.
Not surprisingly, using this Wien bridge circuit, frequency firmness is fine with changes in both supply voltage and temperature.
Sean Walton says
First circuit doesn’t work on a simulator.
admin says
It will work if you build and test it practically
Sean Walton says
Thx. I’ll try it. (What I need now is an oscilloscope… Maybe I can borrow one from work.)
What kind of voltage swing can I expect?
Can I use 2N2222?
Which cap do I tune to get a specific frequency?
admin says
The voltage will swing from 0V to the supply volt level in the form of a sine wave.
yes 2N2222 can be used.
all the 3 caps could be tuned and all the 3 needs to be identical.