Here the power supply failure alarm circuit electronic
Constructing the circuit is pretty simple and easy. The values of the parts will not be crucial. When the alarm circuit is operated from any external DC power supply source, the main supply section up to points “P” and “M” can be omitted from the circuit.
This schematic diagram come from circuit: Power Supply Failure Alarm
Go to that page to read the explanation about above circuit design.
In the electrical sector, a schematic diagram is usually used to describe the design or model of equipment. Schematic diagrams are usually utilized for the maintenance and repair of electronic and electromechanical devices / units. Original schematics were made by hand, using standardized templates or pre-printed adhesive symbols, but nowadays Electrical CAD computer software is often used.
In electronic design automation, until the 1980s schematics were virtually the only formal representation for circuits. More lately, using the progress of computer system technology, other representations were introduced and specialized computer languages were developed, because with the explosive development of the complexity of electronic circuits, classic schematics are getting less practical. As an example, hardware description languages are indispensable for contemporary digital circuit design.