Is there a chip that converts 12VDC+ to 9VAC + and -?

 

You can accomplish this many ways. The general term is inverter but that usually implies a voltage increase as well, such as using a 12V car battery to power a 120V AC appliance.

How much current do you need? Do you know if a square wave is acceptable?

 

There is no + and - ac its alternating current on the other hand, changes direction periodically. The voltage in AC circuits also periodically reverses because the current changes direction.

 

You can accomplish this many ways. The general term is inverter but that usually implies a voltage increase as well, such as using a 12V car battery to power a 120V AC appliance.

How much current do you need? Do you know if a square wave is acceptable?

Need 1 amp and yes a square wave will work. Thanks.

 

Need 1 amp and yes a square wave will work. Thanks.

Do you truly need alternating current, or just a series of DC pulses?
In the former case I recommend an H-bridge driver, something like this. (Just an example, I'm not sure this would meet all your requirements.)

If you just need DC pulses, then I'd recommend a 555 timer IC driving a MOSFET to get to the higher current.

 

I ac

Do you truly need alternating current, or just a series of DC pulses?
In the former case I recommend an H-bridge driver, something like this. (Just an example, I'm not sure this would meet all your requirements.)

If you just need DC pulses, then I'd recommend a 555 timer IC driving a MOSFET to get to the higher current.

I wish it was that simple but I actually need 9V AC peak to peak, swinging positive and negative as if it came from a step down transformer plugged into a wall receptacle. Sine, square, doesn't matter. Thanks.

 

I wish it was that simple but I actually need 9V AC peak to peak, swinging positive and negative as if it came from a step down transformer plugged into a wall receptacle. Sine, square, doesn't matter. Thanks.

Then you have an H-bridge inverter in your future. You might be able to find one pre-built on eBay. I'd certainly shop around before starting to design and build something. Your challenge might be finding one that can operate at 60Hz. The ones for controlling motors wouldn't be expected to work at that frequency. But I don't know they wouldn't. Of course one meant for an inverter would.