and they usually work of the bat.
Expect similar problem as with post #1 schematic. Notice that 32 kHz tuning fork crystal ESR is factor 100 to 1000 higher than MHz crystals. Need at least higher impedance bias network. NJFET instead of NPN may be a good idea.Have not tried it with tuning forks.
I Know, But I wasn't considering the Topic of a Colpitts as being important.chemelec, it is not a sine wave oscillator.
I Know, But I wasn't considering the Topic of a Colpitts as being important.
Crystal model contain coil, which can be 10Henry or more, so capacitance range can be in the range of pFarad at 32kHz. Crystals have series and paralel resonace frequency, the circuit around it will determine that at which resonace frequency it will oscillate, at colpitts it is the series resonant frequency like in most of the cases. Tap point at Colpitts is used to get enough phase shift, and gain is generated by the resonant tank's quality factor. If you put inductor in paralel with the crystal you push up the resonace frequency, and decrease the quality factor and loop gain. At colpitts the non-linear components in its output are smaller, and it is not necessary to use additional filtering, depends on application. Shaped squre wave oscillators, like Pierce oscillator requires more filtering, which in some cases is not the simplest solution.The Colpitts oscillator uses a COIL. That is what gets you a gain greater than unity to oscillate. The junction of the two capacitors works as a midpoint tap when resonating with a coil. Thai is a 2:1 relation from base to emitter. A crystal does not do that. You have no gain here. You can try to place a coil in parallel with the crystal, that resonates close to the oscillator frequency. But 47 pF for 32 Khz??? 47 nF may be closer to what you need. I would just go to a cmos oscillator and shape the output with an LC circuit to have sine wave.
Not necessarily, a crystal can be used in place of the LC resonant circuit.The Colpitts oscillator uses a COIL.
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