Hi Metalfan1185
There are three tanks I wish to control each requiring different temperature ranges both at the hot and cool ends. So the spot bulds are 100w , 75w and 50w respectively. The ceramic heaters are 500w, 350w and 250w.
Fans are 12v similar to the ones found in PC's for cooling but could easily be 9v ones. These again would only be triggered to ensure that no overheating occurred. My thoughts on the control of these was to use a relay to start stop the current and use the heat sensors to monitor the affect with a humidity sensor to ensure that in the one tank I didnt decrease the humidity to much as it is also a factor.
My understanding is that the ceramic heaters can be plugged in and will just heat, however they can be connected to work with pulse proportional thermostats which I understand to be the same as PWM.
The dimming of the spot bulbs based on temperature is normally controlled using a voltage regulating dimmerstat
I seem to remember from my very distant school years that I need to use these calculations however its a little vague so dont laugh to loud
For a 100W spot bulb
Amps can be worked out using wattage/voltage
100/240 = 0.42amps
power is volts x ampheres
240 x 0.42 = 100.80
restistance is voltage / ampheres (ohms law i believe)
240 / 0.42 = 571.43ohms
but from here I am stuck a little, well a lot actually
Is the current flow the voltage / resistance hence
240/571.43 = 0.42
Other than that I am stuck