DC Power Supply Basics Through Comics [HAIKAWA]

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Episode 1What is a regulated DC power supply?

Episode 1 Column

Most electronics, including portable ones, run on electrical power known as direct current, or DC. A typical example of DC power would be a battery. However, batteries have a lifespan and gradually decrease in voltage over time, which is considered problematic when developing and manufacturing electronics.

This predicates a demand for instruments that can provide a constant voltage for long periods of time. The best way to achieve this is with what is known as a “Regulated DC Power Supply” (hereinafter referred to as a “DC Power Supply.”) These instruments convert a commercial power source (alternating current distributed to your home) into direct current that can be used continuously for long periods. There are various types of power supplies that can draw a wide range of voltage and current depending on the application.

In Episode 1, Naoto explains to Minami that the main difference between a DC power supply and battery is the degree of freedom in the output settings. However, there are many more differences as seen in the table below (Regulated DC Power Supply & Battery Comparison). As you can probably tell, it is much more common and practical to use a DC power supply in the workplace. DC power supplies are often thought of as relatively simple tools when used in a professional setting. Customers often skip the user manual completely and play with the front panel thinking that they’ll somehow end up with their desired output. However, this is an extremely dangerous practice when using DC power supplies. As Naoto mentions in the story, DC power supplies differ from other electronics in that they are devices that create electrical energy. Therefore, it is critical to recognize the magnitude (i.e. the danger) of the electrical energy by checking the front panel rating display (Ex: 0-40V/0-5A) and referring to the basic instructions and precautions found in the attached user’s manual.

At the end of the episode, Utsugi asks Minami to read the instruction manual and mark any parts she doesn’t understand with sticky notes. This is quite the tall order for someone not familiar with electricity. Who knows what the user’s manual will look like when she comes back? (I’m sure we can make a guess) This is a common theme among people from different fields (machinery, chemistry, etc.) who try using a DC power supply for the first time. Episode 2 will go deeper into the user’s manual while dropping hints on how to use DC power supplies correctly. We hope to see you in the next episode!

Regulated DC Power Supply & Battery Comparison

Battery Regulated DCPS
Output Settings Fixed Wide range from 0 to maximum rating
Output Mode Constant Voltage Constant Voltage / Constant Current
Continuous Operation Depends on battery capacity Unlimited
Output Stability Output decreases over time Maintains constant output
External Control Not supported Supported
Overvoltage, Overcurrent Protection Not supported
(Possible with external circuit)
Capacity Expansion Available with parallel connection Available with parallel connection
Rush Current Capability Supports instantaneous swells in current up to several times the rating Generally not supported
(Available in some products)
Cost Low unit cost but is a consumable requiring continuous purchases Start-up costs are high but only maintenance costs are electric utility expenses
(not including possible repairs, calibration, etc.)

Episode 1What is a regulated DC power supply?