Abstract A switching circuit for an electronic musical instrument which is generally composed of an emitter-grounded type transistor amplifier in which an input is supplied to a base, an output is taken out from a collector and a key switch is interposed in an emitter path. The emitter is connected serially through a first resistor, a second resistor, a first diode, and the key switch to a power line. A juncture between the first and second resistors is connected to a cutoff potential via a third resistor and to the power line via a first capacitor for giving a decay effect. The emitter is further connected serially through a second diode, a second capacitor and a fourth resistor, to a juncture between the first diode and the key switch for giving an attack effect.
An attack and decay circuit for an electronic musical instrument, said circuit comprising an input terminal and an output terminal; a power source; a transistor having a base connected to said input terminal, a collector connected to said output terminal, and an emitter; a first resistor, a second resistor, and first unidirectional element and a key switch connected in series circuit between said emitter and said power source; a third resistor connected between a juncture of said first and second resistors and a potential point which gives said emitter a voltage rendering the transistor cutoff; a fiRst capacitor connected between said juncture of said first and second resistors and said power source; and a second unidirectional element, a second capacitor and a fourth resistor connection in series circuit between said emitter and a juncture of said first unidirectional element and said key switch.
Claim 2
Dependent Claim
143 words
An attack and decay circuit for an electronic musical instrument, said circuit comprising an input terminal and an output terminal; a power source; a transistor having a base connected to said input terminal, a collector connected to said output terminal, and an emitter; a first resistor, a second resistor, and first unidirectional element and a key switch connected in series circuit between said emitter and said power source; a third resistor connected between a juncture of said first and second resistors and a potential point which gives said emitter a voltage rendering the transistor cutoff; a fiRst capacitor connected between said juncture of said first and second resistors and said power source; and a second unidirectional element, a second capacitor and a fourth resistor connection in series circuit between said emitter and a juncture of said first unidirectional element and said key switch.
Claim 3
Dependent Claim
28 words
An attack and decay circuit as defined in claim 1, wherein there is further provided a charging circuit connected across said second capacitor and having a variable voltage.
Claim 4
Dependent Claim
20 words
An attack and decay circuit as set forth in claim 1, wherein said first and second unidirectional elements are diodes.