1. Transistors and ICs

2. The SCR SCR = SILICON CONTROLLED RECTIFIER In the family of semiconductors that includes transistors and diodes. Controls current in one direction Not all SCRs use the casing shown, but this is typical of most of the high-power units. From http://www.tpub.com/neets/book7/26c.htm The electrical engineering training series http://www.tpub.com/neets/book7/26c.htm

3. Note: the cathode side is towards the negative side of the battery A SCR is very sensitive to too much electrical energy, we use a 1000 ohm resistor to protect the SCR from burning out. Which part of the SCR needs very little current? The gate Which side is the beveled edge? The gate Gate Anode Beveled Edge front anode cathode 220 Ohms + - 9 volts 1K Ohms gate

4. Similar to a basic light switch, transistors have two operating positions, on and off. The transistor is a solid state semiconductor device can be used for amplification, switching, voltage stabilization, signal modulation and many other functions. It acts as a variable valve which, based on its input voltage, controls the current drawn by it from a connected voltage supply.

5. The 555 timer is an extremely versatile integrated circuit which can be used to build lots of different circuits.

6. Integrated circuits are used for a variety of devices, including : microprocessors, audio and video equipment, automobiles and more

7. Integrated circuits are often classified by the number of transistors and other electronic components they contain: SSI (small-scale integration): Up to 100 electronic components per chip MSI (medium-scale integration): From 100 to 3,000 electronic components per chip LSI (large-scale integration): From 3,000 to 100,000 electronic components per chip VLSI (very large-scale integration): From 100,000 to 1,000,000 electronic components per chip ULSI (ultra large-scale integration): More than 1 million electronic components per chip