What ensures that the voltage remains constant in a fuel cell?

In a fuel cell, maintaining a constant voltage primarily relies on the continuous supply of reagents, such as fuel and oxidant. When these reagents are consistently fed into the fuel cell, it ensures that the electrochemical reactions can proceed without interruption. This steady flow helps maintain the reaction rates needed for balanced electron transfer, which is crucial for stable voltage output.

When reagents are consumed, the concentration of active materials can change, potentially leading to fluctuations in the cell's performance, including the output voltage. Therefore, continuous supply acts as a stabilizing factor that prevents the performance from degrading as the cell operates. This is why ensuring a constant flow of reactants is essential for maintaining consistent voltage in a fuel cell setup.