# A rapid review

Before beginning any hands on work for the melody maker, A rapid fire review of the fundamentals of audio electronics was required for me in order to ensure the project runs smoothly. In this blog I will run through concepts that are key to this project so that it may ease the difficulty of the project. You may also learn something however if you choose to stay and read ðŸ˜€

## Fundamentals

First things to focus on were the fundamentals. How do circuits actually work. 2 concepts are key to understanding them:

- Closed loop
- Voltage, Current and Resistance

**Closed loop**: Electrons can only flow if there is a closed loop – a path from the negative to the positive terminal of a battery. An example of where a closed loop occurs is a light bulb. Connecting the light bulb to both the positive and negative side of the battery will allow the electrons to flow in order to make it shine a light.

**Voltage:** Voltage is what makes the electrons move in a circuit. It pushes them onto a wire and the more we have the more ‘power’ we have. In audio more voltage allows for a louder volume. This is why you tend to see small speakers requiring less volts while big loudspeakers or PA systems would require 50 – 100V. V is the symbol for volts.**Resistance:** Resistance is a measure of the opposition to current flow in an electrical circuit. The opposite of voltage you could say. It is measured in ohms. Î© is the symbol for resistance.**Current: **Current can be described as the rate at which electrons flow past a certain point in a complete electrical circuit. It is measured in amperes. I is the symbol for resistance.

**Ohm’s Law**

Ohm’s Law states that electric current is proportional to voltage and inversely proportional to resistance.

To remember Ohm’s law just remember this simple triangle. VIR. Voltage, Current and Resistance. Lets say you want to find voltage for a circuit that you are building. Using the triangle you cover your hand over V and what you are left with is I and R. This means Voltage = Current multiplied by Resistance. Using this formula you can find the voltage if the current and resistance is known. You can also do this with finding the current of a complete circuit. Simply hover your hand over I and we can see that V and R are left. V divided by R = I. Overall this is a simple method to help remember Ohm’s law!

## More to learn

Now that we remember how a circuit works, we must know review what components make up a circuit and what their function is. This will be featured in my next blog.