This circuit was obtained in the Philips integrated circuits manual of 1990. The indicated power is 14.4 V, and the power depends on the load that can be between 2 and 16 ohms.
This simple alarm was found in a 1982 documentation, but uses components that are still common,...
Found in a 1969’s Electronic Design, this circuit operates in a narrow range of voltages....
This experimental circuit was found in a technical publication from 1976. The diode can be of...