Voltage Regulator Circuit

A voltage regulator circuit, or a DC to DC converter, is needed to convert a DC voltage supply, one that is fixed over time, such as a battery, to another DC voltage.

To covert a 110 AC power source (alternating current like the outlets in the wall) into a 5 V DC power source, the circuit would be an AC-DC converter. 

For example, say there are 2 types of batteries connected in a series to act as voltage sources – a 9 V battery and two 1.5 V batteries that are to act as a 3 V source. But, different circuits in your project require different voltage sources, so you may not be able to directly hook the battery to the power circuits.

In this example, one component is designed to function with a constant 5 V source. This means you will have to convert the 9 V battery into a 5 V source. A voltage regulator circuit can make this conversion.

How to Build a Voltage Regulator Circuit

In order to convert the 9 V battery into a constant 5 V source you have to build a voltage regulator circuit. The voltage regulator circuit is made up of 5 components:

1. 9V battery – The 9V battery is a rectangular prism shape with rounded edges and a polarized snap connector on the top.
2. Resistor – This is a passive two-terminal electrical component used to present electrical resistance.
3. Diode – This component has an asymmetric transfer feature, with one low (preferably zero) resistance to current flow in one direction, and high (preferably infinite) resistance in the other.
4. Transistor – This is a semiconductor used to amplify and switch electronic signals and power.
5. Capacitor – This is the component that stores the electrons.

You need to be extremely careful. If you accidentally interchange the base and collector the transistor will be destroyed immediately.

Another thing that could potentially cause a problem is that the capacitor is electrolytic – this means it can only tolerate voltages applied in one direction. The capacitor will be destroyed if the voltages are reversed.