Selecting a laboratory power supply for the lab is not as easy as you might think. If you thumb through a catalog and choose the first one that you think meets your needs, you could end up with a power supply that more often than not sits on the shelf. By filling out the checklist below, and comparing your needs to the product descriptions and specifications of AMETEK Programmable Power's DC bench supplies, you're more likely to get the power supply you need.

Transient response is a measure of how well a DC supply, such as the Sorensen SG Series, copes with changes in current demand or how well the supply follows load impedance changes. This is an important specification in many applications, such as mobile phone testing and testing automotive relays and fuses. A good understanding of this power supply characteristic will help you choose the right supply for your test application.

Electronic loads have many different applications, including testing power converters and modulating a current supply while performing other tests. They are easy-to-use and provide much higher throughput than resistors when varying loads are needed.

When a load draws a high current, the voltage drop across the power leads could be high enough to cause a device under test (DUT) to fail or cause a system to malfunction. The solution to this problem is to use remote sensing. By adding a second set of wires—the sense wires—you can ensure that the proper voltage level is at the DUT or system's power terminals.

You can use electronic loads to test many different devices, including

One of the challenges facing designers of lighting fixtures or luminaires that use high-brightness LEDs (HBLEDs) is testing the low-voltage, constant-current power supplies, called drivers, used to power the LEDs. Making this choice is difficult because the number of LEDS and the configuration of the LEDs will vary from design to design.

In order to perform an accurate test of solar array inverters, the output of a solar array simulator must faithfully follow the I-V curve of a solar array or solar panel. That is to say that it must respond just as a solar array would to the changing load conditions imposed by the inverter under test. In order to evaluate how well a simulator can do this, you need to consider three parameters: output noise current, phase error between output voltage and current, and the maximum power point (MPP) tracking accuracy.

One of the most important specifications for a DC power supply is load regulation. Load regulation is a measure of how well a supply maintains its output voltage when the output current changes. Good load regulation will help ensure that the power supply will deliver the voltage your circuit or system needs.

The slew rate of a DC power supply is the rate at which the output voltage and output current changes. This characteristic is important in many applications, especially automatic test applications, as the faster a supply reaches a programmed voltage or current, the faster a test will run.

The first choice you must make when purchasing a DC power supply for a test system is whether to select a linear supply or switching supply. Linear power supplies offer low ripple and noise specifications and have fast transient behavior. They are, however, inefficient and generate a lot of heat. They are also quite heavy. As a result, most engineers find them desirable only at lower output power levels (typically less then 500 Watts). Most linear DC power supplies are benchtop supplies.