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TEJ 1O - Safety Info
Safety
The practical work done in this course is safe using the equipment provided in a controlled setting, and under careful supervision. Much of the work for this course is done virtually through TinkerCAD and is therefore safe. However, outside of this context, beware that there are potential dangers with robotics (both mechanical and electrical). DO NOT attempt to service your own computers or electronic equipment at home.
Hazards
- Motors can kill.
- Electrocution can kill.
- Electricity can cause a fire that can kill.
- Expensive equipment can be damaged.
- Valuable data can be accidentally destroyed.
Extension Cords
- Use shortest cord possible
- Use the thickest cord possible
- Fully extend the cord rather than using it coiled up
- Never use a plug if the ground pin (3rd pin) has been snapped off.
- Always use power bar and make sure it has a built in breaker.
- Do not stack power bars such that one plugs into another
- Beware of the total amps used by all devices on an outlet (maximum 15A total)
Batteries
Transformers |
AC/DC Transformers (aka adapter, wallwart, power supply) bring the high voltage from the wall down to a low voltage that can be used with common electronic devices. DO NOT plug a random transformer into a random device or you may cause damage. You need to properly match the device and transformer.
Below you can see the input and output specifications on the transformer. The input is what comes in from the wall outlet (120 Volts AC current) but what we are most interested in is the OUTPUT (power going to our device). Output is 16 VAC and can handle 1.25 Amps. The barrel plug in the middle runs from the transformer and is what will plug into our device (in this case a piano keyboard). The barrel plug has two separate contact points and the centre will either be DC positive, DC negative or AC. The piano keyboard has a diagram printed above the power socket. The wallwart and piano are NOT COMPATIBLE as we will see...
Compatibility requires 3 things:
The piano keyboard requires 12V (volts) but the transformer puts out 16 volts.
The piano keyboard is centre-negative (DC) but the output of the transformer outputs AC
The piano keyboard requires 800mA (=0.8 A - not shown so be careful) but the transformer can handle 1.25 A
Conclusion: The transformer above can handle enough amps for the piano, but it has the wrong voltage AND is the wrong polarity, so it fails 2 out the 3 checks.
What is wrong with the adapter below?
The piano keyboard is centre-negative (DC) but the output of the transformer outputs AC
The piano keyboard requires 800mA (=0.8 A - not shown so be careful) but the transformer can handle 1.25 A
Conclusion: The transformer above can handle enough amps for the piano, but it has the wrong voltage AND is the wrong polarity, so it fails 2 out the 3 checks.
What is wrong with the adapter below?