NE55 Multi-channel Waveform Transmitter

 The NE555 multi-channel waveform generator can produce square waves, sawtooth waves, triangle waves, and sine waves. A jumper is used to select the output waveform; the circuit is simple and easy to operate. In the circuit, D1 is a reverse-connection protection diode, and C1 is a filter capacitor. IC1, R1, R2, and C2 form the square wave generator; the signal is output from pin 3 of IC1, and C3 is an anti-interference capacitor. The square wave output from pin 3 of IC1 is divided by R3 and R4, coupled by C5, and shorted by J1 to output a square wave. Another path is coupled by C4 and divided by C3, then passes through an integrating circuit R5 and C7 to form a sawtooth waveform output from J2. This then passes through the next integrating circuit R6 and C8 to form a triangle wave output from J3. After passing through R7, it is amplified by an amplifier circuit composed of C9, R8, Q2, and R9, and finally becomes a sine wave at the collector of Q2. R10, R11, and Q1 form an emitter follower amplifier circuit. The signal is then coupled through C10 and divided by W1 before being output from the output terminal.