# How do I electrostatically charge a plate?

Let's say I have two iron plates (P1 and P2). I want one side of each plate to have an opposite charge.
The surface of P1 should be charged with a positive charge and that of P2 with a negative charge so when I bring the charged sides of two plates closer they should attract eachother. But inorder to achieve this there must be way to charge the plate surfaces with opposite charges. How do I electrostatically charge the plates?

It would be desirable if I can charge the plates using electricity (AC or DC).

• What voltage do you want the plates to be charged to? What is the charge going to be used for? May 20, 2020 at 10:12
• @hdhondt I've not decided yet the voltages to use. I first wanted to know if its possible to charge the plates and methods to do so. May 20, 2020 at 10:21
• In that case, a battery or any DC source will do the trick, as explained by the answers. May 21, 2020 at 4:57

The charge in an ideal parallel plate capacitor in air is given by $$Q = \frac{\epsilon_0A}{d}V$$ where $$\epsilon_0 = 8.854\times10^{-12}\,\text{F/m}$$ is the permittivity of free space, $$A$$ is the plate area, $$d$$ is the separation of the plates and $$V$$ is the potential difference between the plates. Thus the wider the plates are, the higher the voltage and the closer the plates are when you charge them, the greater the charge induced.