Hey guys,ive been given the task of designing a Wien Bridge Oscillation circuit with a design frequency of 4Khz and a design period of 0.25mS for osscillation. Its also using a 741 op amp.
The circuit has an amp gain of 3 so ive got the amplification side of the circuit sorted,just dont know how to get R1,R2,C1 and C2.
Im assuming i would use f = 1 / (2*3.14*R*C) though i dont know where to go from there.
You're better off selecting convenient capacitor values then re-arranging the formula to give you the resistor values.
Resistors can easily be purchased in E24 values, where as capacitors can normally only be purchased in E6 values (E12 if you're lucky) so it makes sense to vary resistor values.
If you're completely stuck for what capacitor values to use, work out C for an impedance value of say 50k at oscillator frequency and round to the nearest E6 value. This should give you a reasonable reasonable resistance value, i.e. not too big and not too small.