# How to add DC offset to a sine wave (so from -2.5V - 2.5V to 0V - 5V)?

I have a sine wave with a minimum peak of -2.5V and a maximum peak of 2.5V. I want to add a DC offset of 2.5V (using a separate power supply so no positive clamper) in order to get a sine wave between 0V-5V.

Can I somehow use the LM324N by any chance since I have that one available? If not, any other IC is also fine...

• What is the lowest frequency that the sinewave can be? – Andy aka May 12 '17 at 10:59
• Thank you both of you, opamp could be there for isolation. – user203 May 12 '17 at 12:12

If the lowest frequency of the sinewave is audio for example, all you need is a decoupling capacitor and a resistor that connects to the 2.5 volt DC offset. Here's how to remove a dc level: -

The output DC level can be restored by attaching the resistor (R) to 2.5 volts instead of 0 volts. If you need to connect to a load that might alter the planned DC offset then maybe you will need to add an op-amp buffer.

A 10 uF capacitor and 10 kohm resistor will have a 3 dB point at 1.59 Hz and this would be suitable for audio signals: -

Can I somehow use the LM324N by any chance since I have that one available?

I don't see any reason to use an op-amp unless you want the input frequency to go down to 0 Hz or you have a significant load to be attached to the output.

It depends how perfect you want the end result to be.
Assuming a fairly low impedance signal source you can normally get away with a series cap, a couple of bias resistors and then an op-amp to buffer the output. The impedance of the RC network needs to be high in comparison to the signal source in order to minimize the impact on the signal and this will act as a filter so you need to pick values to pass the frequency range of interest.

simulate this circuit – Schematic created using CircuitLab