Difference between revisions of "ElectronicsClass"

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* Current limit via wire gauge []
* Current limit via wire gauge []
* Voltage limit via insulation.
* Voltage limit via insulation.
* Magnetic and Electric fields surround an energized wire (what?!)
* And wire will respond with current when moved through magnetic flux
  Get this out of the way early (and often)
  Get this out of the way early (and often)

Revision as of 09:56, 16 June 2010

Electronics Class

This class is targeted at the beginner who wants to learn electronics. It would make a fine prerequisite to the Microcontroller Course or the HAMClass

Required Materials

  • Soldering Iron (25-30w)
  • Solder ( 22ga )
  • Bread Board ( or AshClassBoard )
  • wire 24ga
  • 30ga solid core wire
  • Resistors 10kohm
  • variable resistor 10kohm linear
  • switch [[1]]
  • leds (various)
  • capacitor 470uf (ish) [[2]]
  • pn2222 transistor
  • lm386 audio amplifier ic
  • 1/8 male phono jack
Read The Fine Data Sheet:  They hide secrets in the documentation.


  • Measured in watts (usally)
* 100w light bulb
* 25w soldering iron
* 1500w blowdryer
* 200 horsepower
* 3 tons of A/C capacity
  • The notion of instant work
  • Energy or work is expressed in joules (watt*second). Or perhaps (Kw*H)
  • Power(watts) = Current (Amps) * Volts


There are many like it but this one is mine.
  • Naming of parts
    • metering modes
      • restistance - Ohms of resistance
      • voltage - Volts
      • Current - Amps/Milliamps - check the leads
      • diode check - see [Diodes]
    • leads - plugged into the right ports?
  • Continuity testing
    • set the meter to the lowest resistance mode (200ohms or auto resistance)
    • reads "off scale" when the leads are unconnected, this is an open circuit
    • firmly touch leads together
    • reads near 0 if the leads are crossed
  • Voltage testing
    • set meter to 20Vdc or VautoDC
    • touch leads to metered points
    • the reading on the meter is the difference in voltages between the leads


Hold the cold end.

Soldering ( for our purposes ) is the process of joining electrical contacts with a low melting point metal to make a mechanically and electrically strong connection.

  • Restrain long hair/clothing/jewelry.
  • Clean both parts of waxes, oils or debris.
  • Mechanically fit connections together
  • Clean and wet the iron
  • Heat both parts until hot
  • Apply just enough solder to wet the contact surfaces
  • Wait for the connection to shine smoothly
  • remove the iron an test the connection
    • the meter should find near 0 ohms of resistance between the two parts even when mechanically stressed.
    • the meter should read "off scale" to everything that should be isolated


  • use the continuity meter to diagram the electrical layout of the switch.
  • solder switch to the board.
  • test under power with meter voltage setting


The basic wire is a pipe through which electrons can flow from the lowest voltage side to the highest (conventional current) up to the physical limits of the wire.

  • Current limit via wire gauge [3]
  • Voltage limit via insulation.
  • Magnetic and Electric fields surround an energized wire (what?!)
  • And wire will respond with current when moved through magnetic flux
Get this out of the way early (and often)
  • turn off the switch
  • Solder the 30ga wire ends on to the lab 0 area
  • stow fingers away from wire
  • turn on switch


Not like the NYC variety

Resistors impede the flow of electrons across them; usually to protect components from excessive current.


  • solder resistors, meter and record;
  • compare to ohms law math



  • a favorite led [4]
  • LED ( Light emitting diode ) are diodes with a clear case.
  • electrons only permitted to flow in one direction: cathode to anode
    • there are exceptions [diode breakdown voltage]
  • discontinuous IV curve
  • diode logic
  • the cathode is marked
  • the diode check function of the meter can reveal the correct polarity of a mystery diode with a suspect cathode mark.

Light Emitting Diode

  • the short lead is the cathode
  • LED's need current limiting (see BlueSmokeLab)
  • solder in 1kOhm resistor for the led , although you may use another if you can justify the value
  • Solder in the LED, with the short lead towards the ground.


Printed Circuits


470uf electrolytic cap

Capt.png wikipedia capacitor



  • SPDT - single pole dual throw
  • DPST - dual pole single throw
  • 4P10T - ???
- Map this mystery switchLab
Electromechanical relay is a switch that's controlled electrically.


  • Easy to design for
  • debugging (listen for satisfying click)
  • excelent isolation
  • high power control/$


  • high drive current (mostly)
  • noisy (mostly)
  • slow
  • moving parts (eeew)

a typical relay - map this mystery relay lab


PN2222 N channel transistor

little amplifierlab

  • class A amp
  • DC blocking caps
  • bias resistors
  • fixed gain
  • inverted waveform

Digital Logic


LM386 Audio Amplifier [5]