Dual Power Supplies

A bench power supply is an essential piece of laboratory equipment if you do a lot of electronics or other powered projects on your bench and need a reliable source of power at different voltages. They are very useful tools in testing circuits, as they allow you to adjust the voltage to a specific value depending on what project you are working on. A variable DC bench power supply also allows you to set a maximum current, so if there is a short circuit in your project, the bench supply will shut down, hopefully preventing any harm to some components in your project. Bench power supplies are versatile, accurate, stable and don’t cost companies too much.

When it comes to power, you have four units to be aware of: Current, Voltage, Power and Resistance. It's very important that if you are supplying your circuit with some voltage, your supply can keep up with the current drawn.

Types of power supplies

There are two basic types of power supplies in common use: linear and switch-mode. Both are available on RS Malaysia and can be used as bench DC power supplies.

Linear power supplies operate by rectifying AC line power to create DC and then filtering and regulating it to produce user-selectable voltage or current levels. Linear supplies are heavier because the 50 Hz or 60 Hz transformer and associated filters are physically larger.

Switch-mode power supplies start out the same way, rectifying and filtering AC line input voltage. However, they chop (or "switch") the DC into high-frequency AC at about 40 kHz or more per second, then filter and rectify the voltage again before it reaches the output. As a result, switch-mode power supplies are more efficient than linear power supplies and ideal for projects requiring rapid adjustments to variations in load or input. Being significantly smaller and lighter also makes switch mode supplies portable and well-suited for on-the-go use, especially for models with USB C support. For these reasons, they have replaced linear supplies in many applications.

Areas of application

Bench power supplies are valuable additions to an electrician's toolkit, and some common projects they can be used for include:

• General laboratory use, such as electrolysis and anodising
• Education
• Industry
• Research
• Production
• Workshops

Bench power supply for electrolysis and anodising

When buying a bench power supply, certain uses demand particular attention. For example, laboratory processes like electrolysis and anodising, which require the polarity of electrodes to remain consistent throughout, would only work with DC. This makes a linear power supply ideal for such applications.