Power supply is an electrical circuit that provides power to another electrical device. There are several types of power supplies, but the regulated power supply (RPS) and unregulated power supply (URPS) are the leading ones, based on the types of output. 

Regulated and unregulated powers supplies are commonly referred to as DC power supplies, but even though there is also AC power supplies in use. Batteries, on the other hand, are unregulated power supplies because their output voltage varies with charging and loading state. 

The main difference between regulated and unregulated power supply is:

• In RPS, the DC voltage output is regulated so that the output does not interpret a shift in input voltage. While at the output, the unregulated power supply does not have voltage regulation. Therefore voltage cannot regulate at the output. 
• No variation is observed in the output voltage of regulated power supply regardless of the current drawn by the load. Here the voltage is independent of the current in the load state. In contrast, the output voltage of the unregulated power supply varies with the output current primary due to the high internal resistance of the power supply. 
• RPS is relatively expensive compared to an unregulated power supply as they integrate voltage regulation circuits. On the other hand, the cost of an unregulated power supply is low because of very few components requirements. 
• The regulated power supply utilises a voltage regulator circuit that transforms the AC main voltage to a safe, stable and noisy free DC voltage whereas an unregulated power supply generates a rippled DC voltage only be rectifying the AC. 
• The major application of the regulated power supply includes computers, TVs, mobile chargers, medical and measurement appliance. DC motors, LED lamps, relays, solenoids, actuators are some of the major appliances which use unregulated power supply.