Intro to Electronics- Recognizing Components

What I've Learned


  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:

1st band= 1st digit

2nd band= 2nd digit

3rd band= # of zeros

4th 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.