Low-cost intercom circuit electronic.
For constructing a two-way intercom circuit, two similar units, as shown in figure, are needed for being applied. Output of one amplifier unit connected to speaker of the other unit, and vice versa. For single-battery operation, join corresponding supply and ground terminals of both the units together.
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.