# AC,DC Current Combination

1. Oct 19, 2011

### depthfish

Hi, I currently am having a problem where I wish to combine an AC signal and a DC signal.

What I would like to know, is what parameters must be performed to combine the two together in a format where it would be akin to adding two waveforms.

Aka, if I were to have a 1 Amplitude, Sine waveform(AC current), and then a flat line signal(DC), then how would I in a very basic electronic circuit (1 input current of the AC, another of the DC), so that they would in turn form a new Sine waveform AC current, that had an amplitude of 0.5 (effectively. added together the two waveforms.)

From theory and what I've read from multiple (though unclear) sources, is that to do this I need to give them similar voltages, particular in the AC a similar Instantaneous and Average voltage as the DC current.

Is this correct? If not, what is the proper theory, and real world method for combining these currents into one?

2. Oct 22, 2011

### omkar13

Firstly I'd like to know clearly whether you want to combine AC and DC signals or you want to have an output with ac frequency and dc voltage.If you wish to have it in second way,you can pass the ac signal through a clamper circuit. You can adjust the output by selecting appropriate components.

3. Dec 30, 2011

### depthfish

Wow, I came back after all this time and finally found a reply! I found the solution myself, it was to combine the signals first off, thank you omkar13 even though I'm very late to reply to you. Secondly I found that I was asking the wrong question due to some misconceptions. What I was trying to do was if you thought of 2 line graphs. 1 sine, 1 flat, and you were to add them to each other, you would get a 0.5 magnitude sine wave.

But , instead I had to find a way to do this with voltage; The solution is as you said omkar, utilizing a circuit to regulate the magnitude of the original sine wave, and then to somehow feed control of that circuit (possibly via semiconductors or transistors), so as to allow the magnitude control to give the end result of merged waveforms.

Which, I have gone on to use on my project and tested, which worked like gold (the metaphor!) for anyone who would like to know! Thank you omkar13!