A commercial 220V AC to 12V DC 10A switching power supply is connected to a digital voltmeter amperemeter and encased in a junction box.

It supplies the control unit, the peristaltic pump, and the thermostatic unit by three jacks.

In earlier versions, I utilized individual power supplies for each unit. However,  a single source of power is more correct.  Additionally, it is crucial to have a common ground (GND) for every electronic component. The use of a voltmeter is not mandatory, but it can help monitor the actual current consumption.