Operational amplifier based triangular wave form generator is simple circuit that is widely used in function generators. Here is the circuit for Triangular wave generator using 741 op amp. We know that the integrator output waveform will be triangular if the input to it is a square wave. It means that a triangular wave generator can be formed by simply cascading an integrator and a square wave generator, as illustrated in figure.
This circuit uses two operational amplifiers. First op amp functions as a comparator and next op amp as an integrator. Sawtooth waveform can be easily generated by doing little modifications in the triangular wave generator circuit. In this circuit the ‘non inverting’ terminal of second op amp is grounded, to get sawtooth generator we just need to add a potentio meter arrangement.
You may see: Integrator/RC Low Pass Filter
- Resistors (1kΩ, 12kΩ, 180Ω)
- Op Amp 741×2
- Capacitor (0.1µF)
Working of Triangular wave generator
- Comparator compares the voltage at a point ‘P’ continuously with respect to the voltage at the inverting input, which is at ground potential.
- When the voltage at P goes slightly below zero, the output of comparator will switches to negative saturation.
- Consider the output of comparator is +Vsat, since this voltage is the input of integrator, then its output will be negative going ramp.
- Thus one end of the potential divider R1 R2 is at +Vsat and other end is at negative going ramp. When the negative going ramp attains a value say –Vramp the effective voltage at P becomes slightly less than 0V. This switches output of comparator to –Vsat.
- During this time integrator output will be positive going ramp. When the value of positive going ramp attains +Vramp, voltage at ‘P’ becomes slightly greater than 0V, there by switching comparator output to +Vsat.
- This cycle repeats and generates a triangular waveform
- Triangular waveform can also be generated by integrating square wave from an astable multivibrator.
Design of Triangular wave generator
Components pin out