We found this circuit in a 1980s Motorola documentation. The circuit makes use of common operating and the voltage depends on the used type. The components are for a frequency of 500 Hz.
We find this circuit in an old documentation, but it can be implemented with modern equivalent...
This circuit eliminates transients that are 10% above the zener voltage. The transistor must be in...
A solution for using more than 6 channels in a tone-modulated system that uses LM567 as decoders, is to...