A little mod I made on the square/triangle generator just for fun. The triangle passes through an "all-pass" filter and takes a 90° offset in its phase. A fourth OpAmp is used to have the sum of the two triangular waves. At the positive pin enters only the descending ramp because of the two mosfet used as switches. After a few seconds from the start of the simulation, you'll have the sawtooth in output.
It's for fun as I said, thinking of what you can do with a 4-OpAmp IC and some other component.
Though this circuit hardly finds real applications, it could be used for teaching/learning purposes, showing 4 different OpAmp uses into analog electronics.
(if you connect the n-mos to the all-pass filter output and the p-mos to the integrator output you should have an ascendig ramps sawtooth wave)
