Difference between revisions of "ElectronicsClass"

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* slow  
 
* slow  
 
* moving parts (eeew)  
 
* moving parts (eeew)  
[http://ecommas.tycoelectronics.com/commerce/DocumentDelivery/DDEController?Action=showdoc&DocId=Data+Sheet%7F1308242_T77%7F1104%7Fpdf%7FEnglish%7FENG_DS_1308242_T77_1104.pdf a typical replay]
+
[http://ecommas.tycoelectronics.com/commerce/DocumentDelivery/DDEController?Action=showdoc&DocId=Data+Sheet%7F1308242_T77%7F1104%7Fpdf%7FEnglish%7FENG_DS_1308242_T77_1104.pdf a typical relay]
 
- map this mystery relay lab
 
- map this mystery relay lab
  

Revision as of 17:21, 18 February 2009

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.

Resistoriv.png

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

Diode

Diodeiv.png

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.

Motor

Capacitor

470uf electrolytic cap

Capt.png 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 relay - map this mystery relay lab

Transistor

PN2222 N channel transistor

IC

LM386 Audio Amplifier [5]