Difference between revisions of "General Lab Equipment Obstacle Course"

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(Multimeters)
(Multimeters)
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<li> <b>Measuring voltage</b>
 
<li> <b>Measuring voltage</b>
 
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Connect the  
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Connect two probes to the right most inputs to the multimeter. I would recommend using probes with pointed tips or alligator clips at the end. The bottom input is the common/ground input and the upper right input is the voltage/resistance/diode. input. Turn the dial on the multimeter so that it points to V (with a line/dashed line over it) or the mV symbol. These are DC (or RMS) volt and millivolt measuring modes. These modes with measure the voltage difference between the top input and the common input (Vmeas = Vtop - Vbottom).
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<li>To verify this, touch your two probes together. What does the meter read? Does this make sense? Is there a voltage difference between two points without any resistance between them?
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Revision as of 12:28, 13 January 2016

A general primer in important equipment in a scientific laboratory.


Multimeters

This module will teach you about how to use the Fluke 179 True RMS multimeter. For this, you will need:

  • Rigola DP1308A DC Power Supply
  • Rigola DG1022 Function Generator
  • An assortment of short wires
  • 3 Resistors: 10ohm, 50ohm, 200ohm
  • 4 Capacitors:
  • A diode:
  • A breadboard (or protoboard)

You'll learn more about the Power Supply and Function Generator later, but we'll need a minimum of functionality from them to make measurements with the multimeter.


  • Measuring voltage
    Connect
    Connect two probes to the right most inputs to the multimeter. I would recommend using probes with pointed tips or alligator clips at the end. The bottom input is the common/ground input and the upper right input is the voltage/resistance/diode. input. Turn the dial on the multimeter so that it points to V (with a line/dashed line over it) or the mV symbol. These are DC (or RMS) volt and millivolt measuring modes. These modes with measure the voltage difference between the top input and the common input (Vmeas = Vtop - Vbottom).
    1. To verify this, touch your two probes together. What does the meter read? Does this make sense? Is there a voltage difference between two points without any resistance between them?
  • Measuring current (check that fuse isn't blown!)
  • Measuring resistance and testing for continuity
  • Diode check
  • AC signals, frequency response
  • Capacitance
  • Clamp meter

Power Supplies

  • Digital and Analog
  • Floating and grounding
  • Current/voltage limiting

Function Generators

(Should look at this in tandem with the following oscilloscope discussion)

  • Frequency, amplitude, offset, phase
  • Frequency sweep/ramp
  • Sine, square (incl. TTL), triangle, sawtooth, arbitrary waveforms (possibly a demonstration of Fourier components)

Oscilloscopes

  • Voltage/time scale
  • Coupling
  • Triggering
  • Scope probes
  • Termination
  • Bandwidth, sampling
  • Aliasing
  • Analyzing data: cursors, averaging, math menu
  • Exporting data
  • Analog and digital scopes

RF Signals

  • Measuring RF power
  • Termination and impedance matching
  • Attenuation and filtering
  • Splitters, mixers, and switches

Lock-in Amplifier

  • Basic idea of operation; reason for using
  • Use switch to turn on and off a highly attenuated signal and detect it with the lock-in

Frequency Counters

Measure the frequency of an RF source; map frequency vs. voltage curve of a voltage controlled oscillator (VCO)

RF Spectrum Analyzer

Always be careful to ensure signal input to spectrum analyzer is not too large

  • What does a spectrum analyzer do?
  • Attach wire-loop antenna and find radio stations
  • Mix two RF signals and observe the expected spectrum
  • Measuring amplitude of signal above background
  • Save and export data

Soldering

  • Soldering technique
    • Cleaning iron tip
    • Heat pieces to be soldered (hot iron, short time)
    • Avoid cold solder joints
    • Look for shiny and smooth result
  • Tools of the trade: heatshrink tubing, desoldering pump, solder wick, wire strippers, soldering gun, heat gun, rosin flux
  • Solder end of DB9 cable (using only 4 or 5 conductors) to practice stripping wire, using heatshrink tubing, and creating usable product
  • Construct voltage divider on perfboard with BNC input/output connectors