DI Electronics Workshop

Circuit

• LED - small side = long leg = positive
• Connectors - red wires positive / black wires negative or ground (why GND? GND = grounding for discharge)
• Resistor - if you didn't have it the LED would blow / it makes sure the led does not draw all of the 5v current / 220 Ohms Resistor - red red brown is 22 *10
• Resistance is calculated in ohms. So how do we figure out the current? The Lab power supply has a switch for amps/volts you can see its about 0.01.
• V=IR: See more about Ohm's Law
• Using Multimeter: solid line dc, wavy line ac, turn to 20

• Variable Resistor: aka Rotary Potentometer [use middle pin and side pin]

Arduino

• the big brick is the microcontroller

Trivia

• UK Mains has a 50Hz hum. Depending on where or what time (eg: when eastenders ends and everyone puts on the kettle) this hum will change. It is alleged that you can find out what time or location it is from the hum - mains hum signature. From wikipedia: "Electrical network frequency (ENF) analysis is a forensic technique for validating audio recordings by comparing frequency changes in background mains hum in the recording with long-term high-precision historical records of mains frequency changes from a database. In effect the mains hum signal is treated as a time-dependent digital watermark that can be used to find when the recording was created, and to help to detect any edits in the sound recording"