Tech Tips

What is an AC Power Source (Basic Knowledge)

What is AC power source/AC power supply?

A typical AC power supply that flows from an outlet does not always maintain a constant voltage. It includes voltage fluctuations caused by changes in power consumption of electrical devices connected to the same power source and momentary power interruptions.

Since these fluctuations are not large, they do not pose much of a problem for home appliances with simple structures such as lighting. However, in the case of devices with electronic circuits or precision instruments, it can lead to problems such as malfunction. Therefore, a stabilized AC power supply is necessary to eliminate the effects of voltage fluctuations.

Also, unlike an electrical outlet, a regulated AC-to-AC power source can supply a variety of voltages and frequencies. For this reason, they are also used to simulate situations where there is a possibility of malfunctions such as instantaneous electricity shutdown, harmonic generation, and surges in the testing of electronic equipment.

As mentioned earlier, the electricity supplied from the power supply contains various fluctuations, so it is necessary to check in advance that the device under test (DUT) will not malfunction in such an environment. An AC power source is also used for this check. When conducting power supply tests, an AC power supply is suitable for the actual device under test and each test is required.

Furthermore, this property can be used to reproduce AC power outlets in countries around the world. When making electronic devices with AC input that are used all over the world, stabilized AC power sources are used to test the AC input range according to the power supply conditions of each country and the voltage with the corresponding error.

The following three properties are required of an AC power source.

  • Output voltage stability.
  • Output waveform quality is stable, unaffected by fluctuations in input voltage.
  • Can supply stable power without being affected by the type of load or increase/decrease in load.

Whether it is a DC power supply or an AC power supply, a stable and predetermined output is always required. But in the case of an AC power source, not only the voltage but also the output waveform and the supplied power must be stable.

Types of AC Power Sources

AC power sources can be broadly classified into two types: AC voltage stabilizers and frequency converters. Frequency converters, on the other hand, have the function of maintaining a constant output frequency or outputting an arbitrary frequency.

Therefore, when you are simulating a power supply anomaly, use a linear amplifier type frequency converter. The features of each method are summarized below.

Type Method Small size Efficiency Cost Response time Distortion factor Other features
Automatic Voltage Regulator (AVR)
AC Stabilizer
Slidac   Good Good      
Tap switching Good   Good Good    
Phase control Good Good     Poor High reliability
High distortion
Linear amplifier     Poor   Excellent Good output waveform quality
CV and CF
Frequency converter
Linear amplifier     Poor Good Excellent Good output waveform quality
Output voltage and frequency can be changed at any timing
Switching Good Good     Good Good balance of waveform quality, size, efficiency, and cost
Our AC power sources, DRK, DRS, DRJ series
(Single range)
Good Good       Some can output direct current.
(wide range)
Good Good       Some of them can output DC

Product introduction of recommended AC power source

So, how should a beginner choose an AC power source? First, let's take a look at the current trends. In recent years, AC power supplies have tended to become smaller and smaller, and there is also a demand for more efficient power supplies from the perspective of environmental protection.

In response to this situation, Matsusada Precision has developed a benchtop AC Power Source that is more compact than other companies' products. As of July 2021, Matsusada Precision is the only company that sells AC Power Sources in a benchtop size that can be easily carried by one person.

The DRK series is Matsusada Precision's flagship model, offering not only high-quality output power, but also small size, lightweight, and high efficiency.

The DRJ series is capable of outputting DC voltage as well as AC voltage and has a universal power output terminal (electrical outlet) that is convenient for worldwide product development and testing.

On the other hand, the DRJE series has simple features. It is also important to note that, unlike the other AC power source models, it can only provide AC output.

The features of each series can be summarized as follows.

  Single phase AC output Three phase AC output DC output
High-power, multi-function DRK series
Benchtop size and high performance DRS series  
Benchtop size, multi-function DRJ series
Benchtop size, Simple DRJE series    

Basically, AC power sources output only single-phase AC, but Matsusada Precision's AC power sources can also provide three-phase AC by linking three units.

We recommend the high-power DRK series, but you should also consider the nature of the test you need to perform and the location where it will be installed.