I am trying to power 2 fans and a Peltier module from a laptop power supply with On/Off switches for each being controlled from an Arduino. Sadly, I am having issues.
The power supply is a laptop power supply with an output of 19V and 5.27A. When I connect a fan to it, everything goes well, the fan spins and no problems. But, when I connect the Peltier, nothing happens. If I measure the Volts with the Peltier connected, it reads 0V, but any other time it fluctuates around 20V.
Also, when I measure Amps directly from the power supply, I get 0 amps regardless of anything being connected. If I have the fan connected and spinning and try to measure the Amps, the fan dies until I stop trying to measure (but I measure around ~3A).
So, I am guessing that I am not understanding a basic electricity concept here. Can someone explain what is happening here so I can better understand?