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I recently bought the following small hand-held function generator: http://www.velleman.co.uk/contents/en-uk/p371_hpg1.html

But unfortunately it doesn't have a DC offset control. What is the easy way to add a DC offset control (for example from -10V to +10V range) at the output of this function generator? How to implement it?

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  • \$\begingroup\$ Since this appears to be a battery operated unit,you should be able to simply connect a dc source in series with the output. \$\endgroup\$
    – bhillam
    Commented Dec 8, 2015 at 3:08

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I believe the simplest way to try is to add a battery in series.

However if it will not suit for some reason, open the datasheet for LM358 chip (or other popular operational amplifier) and browse down to "DC Summing Amplifier" circuit. It will simply have this chip and few resistors around. You can sum or subtract signals and multiply them by any coefficients you want with the help of proper resistors.

The only limitation to this solution is when you want high frequencies (far above 1 MHz) or high voltages (chip will work in range up to 30 Volts).

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  • \$\begingroup\$ The lm358 has snags and could give distortion in the crossover region .It is featured on www.badbeetles.com .If you use a proper opamp your approach could work . \$\endgroup\$
    – Autistic
    Commented Dec 8, 2015 at 11:16

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