Fully variableDC bench
supplies with voltage and current meters are great for checking
circuits that operate from odd-ball voltages. They're also essential for
checking the voltage range over which a circuit operates correctly. However, for
a lot of work, they can represent overkill.
Some of the bells and whistles on a typical supply can even be
a drawback, when you're simply trying out an idea for a circuit that must work
from a bog-standard supply rail. For example, on many low-cost bench supplies,
the meters are either too small or too inaccurate to allow you to properly check
that the output is set within tolerance. So you generally have to reach for your
DMM and check the voltages anyway, before even connecting the supply to your
circuit.
