Jul 13, 2018

We are used to hear about tattoo power supplies that can handle 3,4 or 5 Amps and people seems happier as this number increases. But what “Amps” mean and why is so important (or not)?

This will take some time so go first with the basic electrical concepts.

“Amps” is the short version for Amperes. It’s symbol is “A”. It is the unit used to measure Current (I). Current is the amount of electrons passing through an area (cable, water, any material) in a fraction of time. To understand the concept you can compare to a water pipe. The flowrate on the pipe would be the current on an electrical circuit.

Voltage (V) is the other big concept in electronics. It is measured in Volts (V). Voltage is the force that moves electrons. Car batteries storage charges (electrons) up to 12V, the bigger the battery is the more electrons will have inside but always at 12V max. So when it is connected to the circuit 12V will be spread through the car and will feed the sub-circuits. Comparing to the water pipe example, voltage would be the height where the water tank is stored. The more height (V) the more force (pressure) the gravity will make on the water to get down.

Last big concept is Resistance (R). It is measured in Ohms (Ω). Resistance as opposed to conductance is the property of a body to obstruct the current flow. In the water pipe example resistance would be inversely proportional to the diameter of the pipe. The more diameter the more water can flow (A) and the less resistance it has.

(thanks to Sparkfun for the great pic!)

The most basic Law in electronics is called the Ohm Law and says V = I*R.

So we can differentiate 2 main characters in this tale: The Sources and the Loads. Cables are connecting this 2.

Sources generate Voltage and Loads “burn” it. An electric heater just burns when electrons go through it and generates heat. A motor will start turning and will generate movement. Movement is another way of “burning” the electrons. So any Load can be considered a resistor.

The bigger the Heater the more current will need so the less resistance has got. When an electric motor is attached into a car it will consume more Amperes as the car is bigger and it goes faster or upwards.

Cool… we’ve got the concepts: Source, Load, Amps, Volts and Ohms. Next week we will get a bit more inside tatto machines and power supplies.