TOY ORGAN USING OP-AMP 741

PROJECT TOPIC:  TOY ORGAN USING OP-AMP 741 (WIEN BRIDGE OSCILLATOR)

Circuit diagram:

The circuit diagram above show how we have structured a three frequency organ using a Wien bridge oscillator with op am 741. An oscillator is a circuit or device that converts a DC voltage to an AC signal. The above Wien bridge oscillator uses a series RC and a parallel RC of same component value as feedback. This feedback circuit produces a phase delay depending on the frequency.

The output frequency depends on the values of the feedback series and parallel RC circuit.

F=1/2pieRC

The piano circuit above is operated by pressing corresponding keys on Side1 and Side2 simultaneously so as to vary resistance value R of both the series and parallel RC feedback circuit. This in turn brigs out different frequency as different keys are press.

NOTE: For there to be an output, the gain of the circuit above must b greater    than 3.

  The gain A=1+Rf/Rin

  In the case of our circuit Rf= 100k variable resistor

                                            Rin= 47k

Our Tested And Working Circuit