Zener diodes can be used to protect the delicate filament of some special tubes. In the first circuit we have the case where the filament is fed by direct voltage and in the second case when the filament is powered by alternating voltage.
Zener diodes can be used to protect the delicate filament of some special tubes. In the first circuit we have the case where the filament is fed by direct voltage and in the second case when the filament is powered by alternating voltage.