As technology has changed, many products have moved from analog controls to digital ones.

Although digital controls suit many instruments, they do not necessarily suit a bench power supply.

Customer research shows that many users prefer the speed and simplicity of conventional analog controls for setting voltage and current.

Digital controls may offer greater precision, but often at the expense of ease-of-use.

With this in mind, the PLH series has retained the true analog controls of its predecessor.
 

The main disadvantage of analog controls is stability and security. The settings of analog potentiometers can drift over time.

More importantly, the settings can be changed accidentally with potentially serious consequences.

The PLH series introduces S-Lock. One press of the Lock button transfers control of voltage and current from the analog controls to internal digital circuitry.

This offers not just complete security, but exceptional stability as well with each setting controlled by a high resolution instrumentation quality DAC.

To prevent an unexpected voltage appearing on the output when the settings are unlocked, the Lock function can only be released when the output is set to off.

Most laboratory power supplies quote impressive figures for load regulation.

Unfortunately, the impedance of the connection leads can make this a nonsense for regulation at the load.

Although the lower currents of the PLH series makes voltage dro in the leads a less significant problem than with lower voltage power supplies, perfect regulation still requires sensing at the load.

The PLH Series has easy access remote sense terminals - unlike many laboratory power supplies - to ensure perfect regulation and meter precision.

Remote or Local at the flick of a switch

Research shows that engineers choose not to use remote sense for many applications.

The PLH Series makes the choice as easy as possible with a front mounted local/remote sense switch.

Despite the improvements in high frequency switcher design, Linear regulation still offers the lowest output noise and the best transient response (recovery time from a sudden current step).

It also offers the most benign stability characteristics when driving complex load conditions.

Low noise

Despite its high output voltage of up to 250 volts, the linear regulation of the PLH series ensures low output noise of below 2mV rms in CV mode and below 10uA rms in CI mode (<1uA on the low current range).