Michael Charlton
Mr. Diddy
Intro to Robotics
12 May 2015

Vex

Not a lot of people know what a resistor is when it comes to robotics engineering. Well I could help on that. A resistor is a passive two – terminal electrical resistance as a circuit component. Electrical resistance is the shock of a current within a circuit. It clarifies the relationship between voltage and the current. Resistors resist the flow of current, and at the same time, act to lower the voltage levels within currents. This is because some components are unable to function at certain levels of voltage. Without resistors voltage would be excessive for individual components to handle and would result in overloading or destruction. The principle by which resistors work can also be applied to heating elements in irons, toasters, heaters, electric stoves and hair dryers, which dissipate voltage as heat. Variable resistors may function as sensors, switches or voltage dividers. The value of resistors is measured in Ohms. Ohm is the unit of electrical impedance or electrical resistance, named after the German physicist George Simon Ohm (1789-1854), who identified the relationship between voltage, resistance and electrical current. A resistor is read by color-coding. The color bands on a resistor allow you to calculate its resistance. To read a resistor's color code, start with the band furthest to the left; this will be the first, most significant digit. The next band to the right is the second, least significant digit. The third band is the multiplier, and the fourth band is the manufacturing tolerance level. Tolerance is effectively, the margin for error between the component’s actual and its stated value.

LED stands for light emitting diode. It is an electronic part that gives light when it is powered. A LED won’t work if it isn’t wired correctly because it is a diode. A diode only allows the flow of current in one direction. In order for an LED to work it needs a chip of semiconducting material filled with impurities to create a positive – negative junction. When a diode is switched on, electrons are able to recombined with holes within the device, releasing energy in the form of a photon creating light. To wire you will need a few parts. You’ll need LED, a breadboard, some wires, and a 470Ohms resistor. You need to connect one lead of the resistor to the digital pin 5 on the arduino. Connect the other end lead of the resistor to the anode lead of one of the LEDs, and then connect the cathode to ground. A Cathode is one of the two electrodes that pass current through the LED and are attached to the circuit board. The cathode, labelled 'k' or '-' on a circuit diagram, is the shorter of the two pins. The longer of the two electrodes, labelled 'a' or '+' on diagrams. Current passes from the anode to the