Electrical Basics

LED's

Light Emitting Diodes are and electrical device that produces light when the proper voltage and currents are applied. Please remember that the flat side of the LED, corresponds to the negative lead. The negative lead is also shorter than the positive one.

The equation for finding the right resistor is

R=(Vs-Vled)/Iled

Vs= voltage source

Vled = voltage drop across led/forward voltage

Iled = Current draw of the led

R=the value of the resistor to limit current and voltage.

Ohms law

Ohms Law is the fundamental set of equations that describe basic electrical circuits. The equations describe the relationships between voltages, currents, resistance, and power.

Voltage is the difference in potential energy per unit of charge between 2 points in a circuit.

Charge is a property of particles and physical objects measured in coulombs. A charge can be positive or negative depending on whether there is a surplus or deficit of electrons.

Current is the flow of particles (electrons in this case) through a conductor in one direction. The electrons flow from the negative terminal to the positive terminal but, when describing current it is common to say the current flows from positive to negative.

Resistance is measured in ohms. Resistance is the measure of opposition to the flow of electrons.

Power is the measure of overall work being done in watts.

To use the diagram first figure out what you want to solve for and look at that quadrant of the circle. Then look to find the 2 variables that you have. Then apply the equation from the outside of the circle.

If I was looking for current (I) and I knew the voltage (5V) and the overall power (1 watt), then I can apply the equation

I = P/V or I=1/5

The current draw would be 1/5 watts or .2 watts

Breadboards

Breadboards are a fundamental part of prototyping circuits. Bread boards allow you to simply press components and wires directly in without soldering.

Breadboards only work with through-hole components of certain sizes. The spacing is all .1 inches apart. The center row is designed to fit DIP (dual inline package) chips.

As you can see in the picture the two rows on the top and the two rows on the bottom are connected horizontally. The smaller groups in the middle connect vertically in groups of 5.

The Outside rails are usually used for power and Gnd. You should always try to color code Ground as black and power as Red.