Voltage regulator boards are used to regulate and lower the higher voltages provided from unregulated sources. In robotics the regulated and lowered voltage levels are generally 5V or 3,3V logic voltage levels.
Voltage regulators can be open loop or closed loop. The regulating methods of voltage regulators can be mechanical or electromechanical. When high precision and efficiency is not important a simple regulator can be created by using a diode and a resistor. Due to the logarithmic V-I curve of the diode, even if the current is high, voltage deflection remains low.
Electromechanical voltage regulators work by switching. A switch connected to a solenoid retracts when current passes through the solenoid and the circuit opens. Then there is no current passing through the solenoid, the switch returns to its reset position and the circuit closes. By that way voltage is kept at the required level. Switching voltage regulators are more efficient than other voltage regulators.