3 fundamental differences between power supply types

Just as a hole punch punches holes, and a hair tie is used to tie up hair, it’s not too difficult to define what a power supply is for.  However, just as high heels, clogs and high-top sneakers all fit within the ‘shoe’ category, there are also different kinds of power supplies that differ just as fundamentally.  After all, any device that requires electric power will require a power supply of one sort or another to regulate or convert the basic source of electric current – whether an outlet, a battery or a generator – to the device’s ideal or required voltage, current, and frequency.

What that means is that power supplies are almost literally everywhere – from a ship to a laptop and everything in between.  We believe the scores of different power supplies out there – from the power supply PC and other computers use to electric vehicles, welding equipment, military planes, cameras, medical ventilators and literally thousands of other devices and systems – can be placed into 3 basic and overlapping categories:

 

1. Switched or linear?

The power supply PC (personal computer) systems typically require is an example of switched-mode technology.  This type gets its name from the ‘switching’ semiconductor that switches or flicks the power source on and off at very high-frequency many thousands of times every second, achieving very high levels of efficiency with no resistance.  These power supplies are also able to either ‘step up’ or ‘step down’ the required voltage.

On the other hand, a linear power supply does no such switching, resulting in the sort of ‘quiet’ operations required for applications such as amplifiers, data acquisition, and medical and communication equipment.  However, these power supplies can only ‘step down’ the input voltage and are normally bigger, heavier, hotter and less efficient than switched-mode supplies, which is why they were much more popular some decades ago.

 

2. AC or DC?

No, we’re not talking about the heavy metal rock and roll band.  Rather, we’re talking about the two basic types of current: alternating (AC), with its two-directional electron flow, and direct (DC), with one-way flow.  The familiar laptop charger is an example of an AC/DC power supply, because it translates the AC which is more efficient for sending electricity over power lines into the DC required for most common devices.

 

3. Unregulated or regulated?

Finally, a power supply will be described as being either regulated – meaning it will maintain a stable output voltage – or unregulated.  An unregulated power supply does not have a voltage regulator onboard, meaning that whatever level of voltage is going in will be essentially the same as what is going out, with electrical noise being a common result of the inconsistency and fluctuations.  Many devices or systems that are sensitive to power fluctuations require a more sophisticated regulated power supply, whose consistent output voltage will be specific to the power supply in question.

 

The final word: Choose your power supply wisely

It’s important to recognise that while the three distinct categories listed above cover much of the vast spectrum of power supplies, there are other fundamental features to consider as well.  For instance, an uninterruptible power supply is designed to keep a device working for a time even when the source power is cut, while a programmable power supply’s voltage, current, and frequency values can be controlled or programmed remotely.  

But for your particular application, the combination of basic power supply technology type and its features – also including ultra high efficiency or liquid cooling and a number of others – will depend not only on the industry and intended usage but also factors like the operating conditions and budget.  Getting the choice right will require the guidance of an expert, so don’t be shy to ensure that what you buy for your operations will be money well invested.

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