Terrarium VentilationCPU fans are very good for terrarium ventilation purposes. They are small, silent (if run at lower voltage than 12V), and reliable.
If placed inside the terrarium (to blow air along the front glass to remove condensation), you must screen the fan with netting to
prevent frogs from getting inside it. Fans placed on top of the vivarium blowing out the warm air from the upper part of the viv is
a good way to lower the temperature.
1. You need a source for ca 9 Volt DC. The fans do not need many
Amps, so in practice any transformer with an output of 9-12 Volts will do.
2. A rectifier is needed to convert to DC (Two different types are shown).
A small flash-light lamp, and a socket functions as 'resistor'.
3. The fan, mounted on a piece of plexi-glass, with a netting (mosquito-type) and the lamp.
4. Wiring diagram. The fans are connected 'in parallell' to the + and - threads. Each fan should
have its own resistor (a small lamp works very well in this role). Note that CPU fans normally
are sensitive to polarity; they will run only when connected correctly.