A sine-shaping network makes the triangular signal of the VCO, a sinusoidal signal that can be picked up at the pin 2. At pin 3 to set the exact medium voltage and the output amplitude. The additional output at pin 11 also delivers a square wave with the same frequency.

The actual sample structure differs in some details from the data sheet. Thus, only a frequency ratio of 1 was chosen to 100, so a finer adjustment is possible. With the frequency-determining capacitor of 0.1 uF an adjustment range of 100 Hz is reached to 10 kHz. The frequency is changed by using a variable resistor.
The amplitude setting at pin 3 is connected with fixed resistors, so the output voltage is always the same. The switching sine / triangle was achieved with a jumper. On the board, the outputs of the circuit were placed in small wire loops, where the signals can be picked up directly with alligator clips.

The sample design renounces everything that is not absolutely necessary. Many attempts have come out with this simple circuit. But there are some points that could improve it take to build an almost professional function generator. All required circuit details are shown in the datasheet.

Switching frequency ranges from about one switch
Verification of a frequency scale
Setting the output voltage through a second potentiometer
Adjustment to minimize distortion of the sinusoidal signal
Setting of the symmetry of the triangular signal


1Hz - 2MHz XR2206 Function Generator Kit

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Function Generator is an essential laboratory equipment for every electronic. It allows a variety of measurements and experiments. The module described here is based on high quality XR2206 IC. 1Hz - 2MHz XR2206 Function Generator is capable of producing high quality sine, square and triangle waveforms of high-stability and accuracy. The output waveforms can be both amplitude and frequency modulated.

Purchase 1Hz - 2MHz XR2206 Function Generator Kit at Electronics-DIY Store