Refer: Silicon Chip Magazine August 2014
This electronic thermostat is ideal for converting a chest freezer into an energy-efficient fridge, converting a fridge into a wine cooler or controlling heaters in home-brew setups, hatcheries and fish tanks. It controls the fridge/freezer or heater directly via its power cable, so there’s no need to modify its internal wiring. It can even be adapted to control 12V or 24V fridges or freezers.
An improvement on our popular KC5476 TempMaster MK2 designed in Feb 2009. It is easier to adjust, has a wider temperature range, uses less power, and virtually immune to relay chatter problems.
* Temperature range: -23 degrees C to 47 degrees C
* Low quiescent power consumption to below 45mW (1.08Wh/day)
* PCB size: 104 x 80mm
Kit supplied short-form with silk-screened PCB, 30A SPST relay, temperature sensor with clamp assembly and components. You'll need to add your own 240V GPO, fused IEC socket, cabling and case. 12V 150mA power required.