Circuit substrate and electric oil pump

A circuit substrate comprising:

• a substrate;
• a positive terminal and a GND terminal to which a DC external power supply is input;
• a reverse connection protection circuit that includes a MOSFET and protects a circuit in the substrate in a case in which positive and negative connection of the external power supply to the positive terminal and the GND terminal is reversed;
• a first substrate wiring that is connected to a source terminal of the MOSFET;
• a second substrate wiring that is connected to the GND terminal;
• and
• a bypass circuit that causes a current to flow from the first substrate wiring to the second substrate wiring in a case in which an output voltage of the external power supply is equal to or greater than a predetermined value;
• wherein
• the predetermined value is smaller than a withstand voltage between a gate and the source of the MOSFET.