Universal Basic Differential Controller

Differential controllers are used to sense a difference in temperature with temperature sensors. This difference in temperature is then used to regulate the on and off cycles of a pump. The NTC 10K thermistor is commonly used for solar heating applications because it responds well  from 0*F to 250* F. It's also rugged, easy to use and inexpensive and it may be used to regulate either an AC or DC pump. The LM34 sensor is used to display actual temperatures, but this is not a necessary function of a controller. To automate a net heat gain from sunlight a controller need only sense and respond to heat availability. My first differential controllers did this, but my customers  wanted more. They wanted a visual indication of solar heat so my latest BDC ( Basic Differential Controller ) has this as a standard feature. The BDC features include:

  Basic Differential Controller + probes (free shipping in USA)       $85

Priority International Shipping  ( For locations other than USA add shipping )   $25