This triangle wave generator is comprised of an integrator and a threshold detector. The integrator acts as a ramp generator, slowly incrementing the voltage over time until it reaches its maximum voltage. However, unlike a ramp generator, when it reaches its maximum voltage, the threshold detector saturates low and causes the integrator to reverse the process and slowly decrement the voltage over time, until it reaches its minimum voltage. Upon reaching the minimum voltage, the threshold detector saturates high, hence begging the loop again.