Circuit to add a DC Offset to an AC signal

[LynB]

Hi,

I have a system comprised of commercial products. One unit is (basically) a linear motor, which I use to apply an oscillating force to a structure. The frequency range of the oscillations is 70-1600 Hz. The signal driving the linear motor comes from an amplifier that is capable of outputting a signal with a DC component, if it receives a low-voltage input signal with a DC component. A third unit is a low voltage signal generator that can only output AC signals. I want to add a DC component to the AC output of the signal generator so that I can apply a static as well as an oscillating force to the structure. What circuit do I need in order to do that?

Thanks for the help.

LynB

 

[enjunear]

What you need is a handy little circuit called a bias tee. It's basically just a capacitor and inductor.

You'll need to properly size the L and C, but that'll get you started.

 

[alexan_e]

You can use an opamp to add an offset voltage in the input of your amplifier
**broken link removed**

Alex

 

[chuckey]

enjunear your circuit is designed for frequencies 10,000 times higher. LynB get 3 100 ohm resistors,feed ac into one, dc into another, take the spare one as you output. Common all earths. See what happens and recalculate the value of your resistors if required.
Frank