What is an Input Specification?

Issue 11 of Adapter NEWS featured a special on AC adapter terminology Part 2, What is Input Specification. It also describes the relationships between the input voltage and frequency, and between input current and inrush current of AC/DC Power Adapter, so please take a look.

Input Specifications: About INPUT SPECIFICATION

This time, as part of our AC adapter terminology guide, we will explain the Input Specification: INPUT SPECIFICATION.

An example of input specifications from the specification sheet of UNIFIVE AC/DC Power Adapter is shown below.

This time, we will explain the following five items: "AC Input Voltage," "AC Input Voltage Range," "AC Input Frequency," "AC Input Current," and "AC Inrush Current."

UNIFIVE Products Specification Sheet Example - Input Specifications

The figure below shows an example of how to use an AC/DC Power Adapter. Insert the AC plug into a household outlet and connect the DC plug to an electrical Products such as a computer.

"Input Specification: INPUT SPECIFICATION" defines the usage conditions on the AC plug side.

Input Voltage and Frequency

AC Input Voltage and AC Input Frequency define the voltage and frequency that can be supplied to the AC adapter.

The second item, AC VOLTAGE RANGE, specifies the upper and lower limits of the AC input voltage.

If the voltage falls below the lower limit, normal output voltage cannot be obtained. If a voltage exceeding the upper limit is applied, the AC adapter may not operate properly and could be damaged. Please use with caution.

Input Current and Inrush Current

AC Input Current refers to the current flowing on the input side when the AC/DC Power Adapter is used at its rated output current, and is defined as a TYPICAL value.

Since there are individual differences in input current among adapters, the MAX value specifies a limit that will not be exceeded even considering such variations.

When using multiple AC/DC Power Adapter with wiring devices such as power strips, care must be taken to ensure that the total of the TYPICAL values does not exceed the capacity of the wiring device.

Inrush Current refers to the instantaneous current that flows when an AC/DC Power Adapter that has not been powered for some time is connected to an outlet or similar power source.

The waveform observed with an oscilloscope is shown below.

A large current flows, but since it occurs only once instantaneously when connected to the power supply, there is generally little need to worry about wiring devices. However, noise may be emitted into the surrounding space, so caution is required when using electrical Products that are sensitive to noise nearby.

AC Adapter Terminology Guide Part 2: Input Specification: INPUT SPECIFICATION (First Half) concludes here.

For explanations of other terminology and specifications, or if you have questions such as "Which AC/DC Power Adapter should I use for this application?", please feel free to contact us through the inquiry form on our website.

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