The RHM5K-CH unipolar temperature controller from Wavelength Electronics achieves precision control at off-ambient temperatures. The proportional-integral-derivative control loop drives resistive heaters and thermoelectric coolers. Offering a small footprint and high stability of <0.003 ºC, it supplies a drive current of up to 5 A. Onboard 12-turn trimpots control temperature set point, proportional gain and output voltage limit, all of which are user-adjustable. A single 10-pin terminal strip provides easy access to the DC supply, sensor, resistive heater and measurement connections. Features include single supply operation from 5 to 30 V and >27-V compliance with 30-V input. Heat sinking then becomes critical, and a safe operating area tool is available to ensure that the maximum internal power dissipation of the package is not exceeded.