Triangular Wave Oscillator
This design resulted from the need for a partial replacement of the well-known 8038 chip, which is no longer in production and there fore hardly obtainable.
An existing design for driving an LVDT sensor (Linear Variable Differential Transformer), where the 8038 was used as a variable sine wave oscillator, had to be modernised. It may have been possible to replace the 8038 with an Exar 2206, except that this chip couldn’t be used with the supply
voltage used. For this reason we looked for a replacement using standard components, which should always be available.
Circuit Triangular Wave Oscillator
In this circuit two opamps from a TL074 (IC1.A and B) are used to generate a triangular wave, which can be set to a wide range of frequencies using P1. The following differential
amplifier using T1 and T2 is configured in such a way that the triangular waveform is converted into a reasonably looking sinusoidal waveform. P2 is used to adjust the distortion to a minimum.