This chapter introduced how electronics are used and how they work together. The three primary measurements of electricity are voltage, current and resistance. Voltage is measured in EMF, current is measured in Amperes and resistance is measured in ohms. (http://merriam-webster.com) Circuit: A usually circular line encompassing an area. The circuit is the bridge between a and b. If it is not all the way connected to the destination point, it is known as a short circuit. PCB is short for Printed Circuit Board and are sometimes also called printed wiring boards. (http://learn.sparkfun.com). Electromotive Force or E.M.F. is the voltage developed by any source of electrical energy such as a battery or dynamo. (http://wikipedia.com) From the electronics, they are divided up and called analog and digital circuits. Analog is a circuit carrying a continuous or changing voltage (v). Moving in two different ways series or parallel. Digital, instead of changing voltage (v) it transmits information. These digital circuits are either alternating or direct currents. Some direct currents would be: batteries, solar panels and low voltage applications. An alternating current would mean switching from on to off, up or down, etc. I got more out of this chapter than is typed I feel, but it is always good to re-read and refresh the memory. However, these are the basics so I can only see hands on and learn more from there. Thank you for the program this is a great way to remember what I learned.