The difference between dc power supply and ac power supply

Taking 12V dc power supply and 12V ac power supply as examples, the differences between dc and ac power supply are analyzed from the aspects of loss, use, measurement and safety.

Direct current is not suitable for long distance transmission because of its high transmission loss.

Alternating current has low transmission loss, so it is suitable for long distance transmission

The dc voltage is stable and there is no white noise. Therefore, it is suitable for the use of electronic products (such as TV set, radio and computer, etc.).

Alternating current (ac) is converted into direct current (dc) through rectified/switching power supply (switching power supply) for use in electronic products

Difference in measurement of 12V ac/dc:

Measure with digital multimeter, measure with 20V ac voltage and 20V dc voltage file respectively, the result will be different, simple measure method: use induction pencil (non-ordinary electric pen) outside the wire sheath,12V ac will still have obvious current and no display safety

12V direct current is safer than 12V alternating current. When the resistance of human body is reduced,12V alternating current can still shock the dead, while 12V direct current cannot shock the dead in 100% case