ECE 480

 

Mandatory Safety Requirements

1.                 Portions of any circuit that can be operated above 50 volts must be protected by a box enclosure or a plexiglass cover.

2.                 The same requirement applies to circuits connected to high current sources (such as lead-acid car batteries) that can output more than 1 amp of current. (Use a box enclosure or a plexiglass cover.)

3.                 Any circuit that plugs into a wall (110 volt) outlet or any circuit that connects to a high current source (such as a lead-acid car battery) needs to have a fuse installed in the power supply circuit.

4.                 Two people (you and someone else) need to be present in the room whenever you are working with voltages of 50 volts or greater or circuits with large current supply capabilities (greater than 1 amp). In general it is always a good idea to work on electronics only when another person is in the room that can get help if something goes wrong.

5.                 Do not wear loose metal jewelry around your wrist or neck when working with electronic circuits. The metal jewelry can touch the circuit creating shorts that destroy the circuit and possible hurt you.

 

 

Practical Advice

Put a capacitor (~0.1 microfarad) between +VDD and ground near some or all of the IC chips on a board. This provides a more stable power supply voltage to individual IC chips.

 

 

Electrostatic Discharge (ESD)

 

Handling of ESD sensitive parts. – you can generally assume all chips and circuits in this class are ESD sensitive

 

1)      Always keep chips in antistatic carrier. (Especially CMOS)

2)      Do not pass chips or boards from person to person.

3)      When you feel a shock from static electricity- it is several thousand volts. (Less than 10 volts can damage many circuits!)

4)      Always touch a good ground before touching your circuit. For example, touch the metal chassis of the computer.

5)      For some particularly sensitive chips you may need to use a static pad and/or a wrist strap.