Dc is on a laptop but can I use an ac power supply?

Thank you question in advance

The laptop needs DC.

AC (AC) comes from the home socket.

The power pack of a laptop converts the high socket voltage AC into a smaller voltage DC. Example: socket 230V AC to 19V DC.

If you have a power supply that now converts 230V AC to lower voltage again, you can't use it for your laptop.

Reputable companies install reverse polarity protection at the input for the supply voltage. This also protects the laptop from destruction when AC voltage is applied.

But nothing more, it won't work.

I would not dare to apply AC.

Basically, you always have an ac voltage that must first be rectified, smoothed, suppressed and stabilized. At the input of a power supply you should have information that an AC 230 Volt 50Hertz voltage is or should be fed.

You should then have a DC voltage at the output that is approved for your device. As a rule, the plugs are also coded, so that only this plug fits in your laptop.

Basically, your laptop does not work with a pure ac voltage. In the worst case, the supply can destroy an ac voltage that is large enough if the device does not have the appropriate overvoltage and reverse polarity protection.

Such reverse polarity protection is often only a diode that allows current to flow in one direction only. Since alternating voltage is sometimes +, sometimes -, only a half wave comes to the laptop. During the other half-wave, the diode is blocked, so that only zero arrives. The right is not and is too wavy.