Operating conditions for the vibrators of photoelectric devices

Conclusions

In constructing an optical-photoelectric device containing a vibrator, the frequency of the current supplying the latter is usually either made equal to the mains frequency, which simplifies the construction of the system, or else made different from the mains frequency but lower than the resonance frequency of the vibrator, which reduces the power required by the vibrating unit. In neither case is the effect of the higher harmonics in the supply current on the operation of the vibrator taken into account. If, however, the frequency of the supply current is lower than the resonance frequency of the vibrator, then the presence of higher harmonics in the supply current will worsen the sensitivity threshold and the stability of operation of the optical-photoelectric device. In order to improve these characteristics, it is essential that the resonance frequency of the vibrator should differ from one of the higher harmonics of the supply-current frequency by at least 7%. If at all possible, it is better to make the supply frequency greater than the resonance frequency of the vibrator.