This is the tone booster circuit electronic. The tone control circuits attenuate the high or low frequencies of the signal. This is called treble or bass “cut”. The simplest tone control circuits are passive circuits which utilize only resistors and capacitors or inductors. They rely on the property of capacitive reactance or inductive reactance to inhibit or enhance an AC signal, in a frequency-dependent manner. Active tone controls may also amplify or “boost” certain frequencies. More elaborate tone control circuits can boost or attenuate the middle range of frequencies. Tone booster was same type with tone control, the different is that tone booster is “fixed”, no adjustment.
This schematic diagram come from circuit: Tone Booster
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.