Wrong schematic!

[cfrigioi]

Hi there, the schematic is completely wrong. The current polarity won't be reversed in peltier. The only thing this circuit can do is to act as an electrodynamic brake, I guess this is where the original diagram came from. But for a peltier it won't work to reverse it's polarity as it is right now. The typical way of reversing the current flow in a circuit is with a H-bridge (with mosfets or relays). In addition to current reversal, the circuit can also act as a electrodynamic brake. Here are some examples:

This is for relay H-bridge

and this for Mosfet:

Regards,

Ciprian