Circuit Schematic Diagram of Op-Amp Oscillator


This operational amplifier circuit diagram can be operated at low frequencies with relatively small capacitors, it can not hang up and always self start because of the less dc positive feedback than the negative one. It also has a completely symmetrical output waveform along with buffered output. The symmetry can change by returning R2 to some voltage other than ground.

Operational amplifier (op amp) oscillator circuit

Capacitor and resistor across pin 1 and 8, which are the usual frequency compensation components, are not needed in this circuit. This is because the op-amp is used in open-loop configuration. It will  only slow the performance if we use frequency compensation components. Furthermore, the use of the circuit is restricted to frequencies below about 2kHz by the speed limitations of LM101, even without a 30 pF compensation capacitor.

The timing capacitor acted by the C1. It produces several times constants which is used to permit large voltage swings on the input due to the LM101′s large input voltage range. The value of R2 should be reduced and the value of C1 should be increased to keep from exceeding the rating. The smaller polarized capacitors is still used, although C1 requires the large values, by returning them to positive supply voltage instead of ground. [Source: National Semiconductor Application Note]


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