This circuit is from Delco Radio found in a 1968’s documentation. The transistors are of the time and are not given information about the driver transformer. Note the high supply voltage.
This additional bell circuit was found in the February 1994 Electronics Now magazine. The...
This 1967 Electronics World circuit is suitable for frequencies up to 1 MHz. The setting applies...
This high power circuit was found in a Popular Electronics of the 90s. The circuit makes use of...