Positive triangular waveform generator

This circuit contains a small addition to the usual two opamp square/ triangular waveform generator. This is the diode included in the feedback loop of IC2 and is responsible for the rather strange behaviour of the oscillator. The triangular waveform output is entirely positive in contrast to a conventional circuit. Without the diode the output will be a waveform that is symmetrical about the zero axis. All this is necessary because some equipment, such as curve tracers, are unable to process a negative waveform. We start the operation of the circuit with IC2. When the output of this opamp goes negative the diode will conduct passing the negative potential to pin 3 (non-inverting input). Since the inverting input, pin 3, is grounded the output will remain negative. This output is also fed to the inverting input of IC1 via R1. The output of this opamp does not change suddenly however, but due to C1 charging, begins to rise at a linear rate. When this voltage reaches the point at wh...