I have an electric stove and what i did was put a pot of water on it and turn the knob to different numbers (from 10 - High to 1 - Lo), starting at the lowest temperature and working my way up. I let the water sit on that temperature for two hours then took the temperature and write it down:
1 - 135 degrees
2 - 140 degrees
3 - 146 degrees
4 - 153 degrees
etc.
When i mash, i first heat it all up to the temperature i am shooting for then set it on the stove turned to the appropriate number. This way i know that in two hours, the mash will get no hotter than my measured temperature. So, if i am going Belgian, for example, i heat up the mash and set the stove for number 3 and let it warm up. When i hit my target temperature, i move the mash over to that pre-set coil and start my mash timer.
no pictures sorry.