Found in American documentation from the 1980s, this circuit prolongs the ringing of a doorbell or chime powered by a 6 V continuous voltage. The transistor can be a BD136.
This circuit was obtained from a 1967 General Electric manual. The circuit uses components of the time,...
This circuit uses an amplifier from National Semiconductor, uncommon nowadays. The numbers in...
This circuit is powered by the source of the equipment under analyze. We found this configuration in a 1974...