Electrical – How to offset AC voltage with varying input

acoffsetsinevoltage

I want to offset an input sine wave, while being able to adjust the input voltage.

For example a sine wave of +-3 V should be offset by 1.5 V such that the sine wave never goes below 0 V. However I want the same circuit to be able to offset correctly +-2 V by 2 V, such that the lowest point of the negative cycle (-2 V) would remain exactly at 0 V once the offset is introduced. The same goes for +-1 V with an offset of 1 V etc.. I am looking to be able to offset 0 – 3 Vpp input range.

I have thought of connecting a variable resistor as a voltage divider
across a well regulated voltage, and buffer the output by using a follower amplifier, however I do not wish to stay doing this manually.

What would be a good approach to go about implementing the above? Any ideas would be appreciated.

Best Answer

Thanks to vofa's comments I found the below Positive Unbiased Clamp.

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As per the referenced web page:

In the negative cycle of the input AC signal, the diode is forward biased and conducts, charging the capacitor to the peak negative value of VIN. During the positive cycle, the diode is reverse biased and thus does not conduct. The output voltage is therefore equal to the voltage stored in the capacitor plus the input voltage, so VOUT = VIN + VINpeak.

This circuit will do the job.

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