Definitions:

1. Multimeter- a device used to measure voltage, current, or resistance.
2. Voltage- a measurement of the electric field potential to create a current in a conductor.
3. Current- a measurement of how much charge moves through a circuit during a specific period of time.
4. Resistance- how freely electrons can flow through materials because of a voltage (move less freely= more resistance and less conductivity)
5. Ohm’s law- relates voltage to current and resistance. V= I*R

I. Basic Electronic Components:

a. Resistors:

• Restrict the flow of electric current.
• Can be connected to circuit either way.
• Are not damaged by soldering.
• Resistor colour code:

1^st band= 1^st digit

2^nd band= 2^nd digit

3^rd band= # of zeros

4^th band (can be ignored)= tolerance

There are also special bands: Gold= x0.1, Silver= x0.01

 

b. Variable Resistors (AKA Potentiometers):

• Have a resistance track and wiper that moves along as you turn a spindle.
• Linear tracks- the resistance will change at a constant rate.
• Logarithmic tracks- the resistance will change slowly at 1 end and rapidly at the other.

 

c. Capacitors:

• Store electric charge.
• Polarized Capacitors (AKA Electrolytic capacitors)- must be connected a certain way in the circuit. Note: the long lead is positive. Polarized caps aren’t damaged by heat from soldering.
• Unpolarized Capacitors can be connected either way and also will not suffer heat damage from soldering.
• Capacitors have the same colour/number code as resistors.

 

d. Diodes:

• Allow electricity to flow in only 1 direction (like a valve).
• Have polarity and thus must be connected a certain way. Note: the side with the line on it is negative.
• Signal Diodes- used for small currents. Process information in circuits, and protect transistors and ICs (integrated circuits) from high voltage.
• Rectifier Diodes- used for large currents. Convert AC (alternating current) to DC (direct current) in a power supply.
• Zener Diodes- used to maintain a fixed voltage. Will allow electricity to flow both ways.

 

e. Light Emitting Diodes (LEDs):

• A different type of diode.
• Will emit light when an electric current passes through them.
• Should not be hooked up directly to a power source.
• Have polarity and thus must be connected a certain way. Note: the small lead is negative.

 

f. Transistors:

• Have polarity and thus must be connected a certain way or they will be immediately damaged.
• Can be damaged by soldering heat, so you should use a heat sink when soldering.
• Amplify current, voltage, or can be used as a switch.

 

g. Integrated Circuits (ICs):

• Complex circuits that are etched into tiny semi-conductor chips.
• Can be damaged easily by soldering heat, so you should use an IC holder when soldering and then pop the IC in.
• Many are static sensitive.