A description of a four-phase RC oscillator of a sinusoidal and rectangular shape is given. A triangular-shaped signal is obtained by the counterphase addition of half-waves of sinusoidal signals ...

The circuit is a triangle waveform generator that uses as few parts as possible. A 555 timer IC, 2 resistors and two capacitors make the triangle wave. The IC is connected in a 50% duty-cycle astable ...