AN-112: Single Resistor Control Wien Bridge Oscillator Frequency

by James Wong Download PDF

Frequency control can be added to the conventional Wien bridge circuit by adding an op amp inverter (A1 in the diagram). the low power OP-221 dual works well in this circuit. The center frequency is 1/R1C1 multiplied by variable term 1/√α. The inverter gain is 1/α where α is a nominally unity. 

The center frequency is given by:

Equation 01

This circuit adds tuning capability to the Wien bridge Oscillator circuit.

Figure 1.

Figure 1.

Author

James-Wong

James Wong

Mr. Wong is a RF Product Marketing Manager at Analog Devices. He served in senior marketing and sales roles for more than 25 years. Additionally, he has been designing RF, analog circuits and systems for more than 25 years.