ElectronicsClass

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.

Metering

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

Soldering

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

SwitchLab

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

Wire

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.

BlueSmokeLab

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

Resistor

Not like the NYC variety

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

• Ohm's law
• Diagonal IV curve.
• symmetric

ResistorLab

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

Diode

ScaryDataSheetLab

• 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)

LEDLab

• 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.

Capacitor

470uf electrolytic cap

wikipedia capacitor

Relays/Switches

Codespeak

• SPDT - single pole dual throw
• DPST - dual pole single throw
• 4P10T - ???

- Map this mystery switchLab
Electromechanical relay is a switch that's controlled electrically.

pros

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

cons

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

a typical replay - map this mystery relay lab

Transistor

PN2222 N channel transistor

IC

LM386 Audio Amplifier [5]