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Course status. Course materials. Lab access Everyone should have lab book proto board voltmeter jumper wires resistor card Write name on yours maintain -- example battery in voltmeter. Electronics maintenance tips. Voltmeter has battery turn off when not in use
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Course materials • Lab access • Everyone should have • lab book • proto board • voltmeter • jumper wires • resistor card • Write name on yours • maintain -- example battery in voltmeter
Electronics maintenance tips • Voltmeter has battery • turn off when not in use • Soldering iron corrodes if left on all night
Course status - basics • Enough to get started in lab • Machine safety • Mount assembly • Optics cleaning • Mach Zender alignment • Basic electronics -- diff amp, integrator • Soldering • Lab book writeups of above skills
Next step • Proficiency demonstrations • like test questions • if done correctly -- full credit • otherwise -- partial credit • compare to others to be sure same performance gets same grade • Written tests • first test is sample -- next class period
Lab proficiency demos • Second optical mount assembly • Construct and align interferometers • Michaelson • Sanac • etalon • white light interferometer • Iris alignment • Others ? • Spatial filter • Confocal etalon • Acousto optics setup • Fabry-Perot filter setup • Stabilize laser intensity using simple servo • acousto-optic shifters, VCOs • Lock optical spectrum analyzer (Fabry-Perot) to laser • lock-in amplifiers and ac servos, etc. • Construct servo box • design and packaging of special-purpose electronics • Optimize both servos and Bode plots
Soldering • Steps to get good joint • Melt drop of solder on iron • Contact work • Flow solder directly on both work pieces • can “tin” in advance • Last action • contact with fresh flux • can be in fresh solder • Too much solder ? • remove with pump or wick • Learn to be fast -- heat damage can result
Op amp debugging tips • Check dc voltage at key pins of op amp chip • Pin 4 = -15 V, Pin 7 = +15 V • if not, check power supply, grounding • Pin 6 (output) • if greater than +/- 10 V -- saturated ? -- check inputs • Pin 2 (+ input) = ground (or reference voltage) • if not, connect • Pin 3 (- input) = pin 2 • if not -- saturated, output load impedance, bad op amp • Saturated ? • Check voltage at each resistor connected to summing junction • set to zero ? • Feedback path closed ? -- short integrator • Check ac voltage at pin 6 • MHz oscillation ? -- add capacitors on power leads • above 1 micro Farad -- electrolytic -- observe polarity
More machining • Second set of mounts • learn tool change • tool sharpen (lathe) • machine setup an tear down • cleanup • Testing of mounts • stability -- nothing loose or vibrating • operation -- knobs and levers work • far field test (mirrors)
screen marks Laser beam laser mirror Long distance screen Far field test -- mirrors • Deflect laser beam with mirror • send long distance • shine on card and mark position • test alignment and stability
Iris 1 Iris 2 Optical sub-assembly Mirror 2 Mirror 1 Input Iris alignment • Align optical sub-assembly • interferometer ? • Place irises in position • one close to second mirror • the other far from second mirror • Disturb input laser beam alignment • Reset alignment using only input mirrors and irises • first center on close iris (1) using mirror 1 • then center on far iris (2) using mirror 2 • iterate