The more sensors and alarms included the better! SECURITY CIRCUITS YOUR MISSION: Create a security system using the Electronic Snap Circuit Kits. Each team needs to design a system that will include at least one sensor and two ways to alert that there is an intruder (sight, touch, hearing). The more sensors and alarms included the better!

SECURITY CIRCUITS Sensors include: photoresistor (light detector), microphone (sound), press switch (touch) Alarms include: whistle chip, speaker, music circuit, space war circuit, alarm circuit, motor (fan), LED light, lamps

Ohm’s Law If You compare electricity to Your house water system: Voltage is a Water Pipe Current is a Water Flow Resistance is a Valve(or a tap) Now, You can imagine that the bigger the Water Pipe the bigger Water Flow is. Same with electricity, the bigger the Voltage, the more Current You can get. If You have a Valve(or a tap) You can reduce Water Flow with it because size of the Water Pipe is reduced at that spot (if You get what I mean), hence with Resistance (Resistor) you can reduce Current by creating a Voltage drop at a certain spot in a circuit.

Ohm’s Law I - Current V - Voltage R - Resistance

Transistor Let's see if I can do better. Here is a picture of a transistor. My transistor runs on water current. You see there are three openings which I have labelled "B" (Base), "C" (Collector) and "E" (Emitter) for convenience. We provide a reservoir of water for "C" (the "power supply voltage") but it can't move because there's a big black plunger thing in the way which is blocking the outlet to "E". The reservoir of water is called the "supply voltage". If we increase the amount of water sufficiently, it will burst our transistor just the same as if we increase the voltage to a real transistor. We don't want to do this, so we keep that "supply voltage" at a safe level. If we pour water current into "B" this current flows along the "Base" pipe and pushes that black plunger thing upwards, allowing quite a lot of water to flow from "C" to "E". Some of the water from "B" also joins it and flows away. If we pour even more water into "B", the black plunger thing moves up further and a great torrent of water current flows from "C" to "E".

Resistor Resistors “resist” the flow of electricity and are used to control or limit the electricity in a circuit. Increasing circuit (+) resistance reduces the flow of electricity. Materials like metal have very low resistance (<1Ω) and are called conductors, while materials like paper, plastic, and air have near-infinite resistance and are called insulators.

Capacitor A capacitor is considered a "passive" device because it does not actively affect electrical currents or other electrical components. Instead, capacitors store electrical energy between electrical conductors. The numbers printed on the capacitor refers to the amount of current it can passively hold. (Ohm’s Law!) Capacitors help regulate electrical current.