The condenser microphone fitted inside a position to catch the sound and generates AC signals, which pass by means of DC blocking capacitor C1 for the base of transistor BC549 (T1). Transistor T1 as well as transistor T2 amplifies the sound signals and delivers current pulses within the collector of T2. When audio is generated in front from the condenser mic, Triac1 (BT136) fires, activates the light plus the bulb (B1) glows for about two minutes.
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.