## What is Alternating current (AC)?

Alternating current referred to as the AC, it refers to the size and direction of time with the periodic changes in the voltage or current, such as household power.

## What is Direct current (DC)?

Direct Current, referred to as the DC，also known as “constant current”, the constant current is a direct current, the size and direction of the constant DC, such as batteries, lead-acid batteries.

## What is the difference between AC and DC?

Now, we use 12V DC power and 12V AC power to analyze the difference between DC and AC power from loss, use, measurement, and safety.

Loss
DC transmission loss, it is not suitable for long-distance transmission,
AC transmission loss is small, so suitable for long-distance transmission,

Use
DC voltage stability, no big noise, it is suitable for the use of electronic products. (such as televisions, radio computers, etc.)
AC power to go through the rectifier/switching power supply into DC power can be used for electronic products.

Measure the difference between 12V AC and DC:
A) with a digital universal measurement, respectively, with 20V AC voltage and 20V DC voltage file measurement, the results will be different.
B) simple measurement method: with a stylus pen (non-ordinary pen) on the wire foreskin, 12V AC will still show, 12V DC no display.

Safety
12V DC is safer than 12V AC. Body resistance decreased when the 12V AC still may cause the dead, 12V DC will not be in 100%.

Peak
According to the voltage pattern, 12V AC and DC instantaneous peak voltage is not the same, the instantaneous peak voltage (12V straight) ≡ 12V, instantaneous peak voltage (12V AC) = √2 × 12V

Conversion
2V AC to 12V DC: Simple (Diode Capacitor Regulator)
12V DC to 12V AC: Complex (Starter )
12) Use – most can think so (for most equipment):
12V DC device 12V AC power supply (burn equipment)
12V AC equipment 12V DC power supply (equipment use efficiency is reduced)

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