General Equipment List
This webpage has a list of all "general-use" equipment used in the Physics Introductory Labs at Stony Brook. It does not include the very basic (meter sticks and the like), nor does it include apparatuses designed for one setup; those can be found on this webpage instead.
Each section has a short description of the instrument, a picture of the instrument, and a link to a longer document with more details about the instrument.
Many of our labs use a digital instrument interfaced with the computer. LabPro and LoggerPro form this interface.
The LabPro is the green box mounted to the wall (or the small gray box on the tabletop), and serves as the hardware that allows the sensors to communicate with the computer.
LoggerPro is the program that takes the input from the LabPro box and presents it to you on your screen. It has a wide range of capabilities, and we use only a few.
A few labs use digital temperature or pressure sensors, which work well enough without any special instructions. Most, however, will use a photogate (see below), for which LoggerPro requires additional instructions.
Accordingly, most labs will have a premade "LoggerPro file" that you should open to do that lab (rather than opening LoggerPro directly). This file contains instructions about how to present the data to you: what data it should show, what plots it should make, etc.
For more information, see this document.
One key instrument many of our labs make use of is the photogate.
This is a small U-shaped piece of plastic with an LED that is fired across the mouth of the U at a light sensor. If the light sensor does not detect light, the photogate is "blocked" (i.e., something opaque is in the way); if light is detected, it is "unblocked."
This sounds like a simple observation (and it is), but we can do a lot with it. Knowing the times (with a high degree of precision) when the photogate transitions from blocked to unblocked is more valuable than it seems.
Combined with an understanding of what is causing it to become blocked and unblocked, we can extract more information about the process of blocking and unblocking. At their core, our measurements are usually a two step process:
- Measure how big some object is.
- See how long it takes that object to pass through the photogate.
Many of our measurements are a bit more clever than that: we often take a "comb-like" structure that repeatedly blocks and unblocks the photogate, allowing us to measure position over time. Sometimes we also use the simpler "one-object" approach (which works fine if there is good reason to think that the object is moving at approximately a constant speed).
A few other pieces of specialized equipment that we use in conjunction with the photogates:
- Picket Fence: This is a striped piece of plastic, with evenly-spaced stripes.
- Ultra Pulley: This is a low-friction, low-moment-of-inertia pulley with ten identical spokes which are designed to block the photogate. A zero-thickness string thread through the outer groove on the pulley moves a distance 0.015m/spoke.
For more information about how the photogate works and how to troubleshoot it, see this document.
We often want to work in a near-frictionless, gravityless (i.e., horizontal) environment. Our air tracks (and corresponding carts) enable us to do this (to a reasonable degree of precision).
These are a one-dimensional analogue of an air hockey table: a constant stream of air lifts (sufficiently light) objects off the surface of the track, resulting in essentially no friction.
The air tracks can also be adjusted until they are flat by turning a screw on the base of one of its legs to raise and lower that leg. You can observe whether it is flat by seeing whether a cart placed on the track moves to one side or the other.
For some, this screw may not suffice, and you may need to put something else underneath the leg to lift it (and then use the screw for fine adjustments).
Some also may be slightly bowed (bent down in the middle), and may not be perfectly level in all locations at once. Level the air track in the center; this will generally suffice for our level of precision.
Our carts are designed to match the angle of the air track, to avoid friction. If you notice your cart having significant friction, comment to your TA, so that this can be rectified.
Some carts have a metal "flag" on the top, which is designed to be detected by a photogate. You place a photogate on a mount on the side of the track, hovering over the track, so that it can detect this flag as the cart passes by.
Other carts have a photogate mounted on top. This photogate is designed to detect a picket fence mounted on the top of the air track. The photogate has an attached LED, and the LED lights up when the cart is [blocked/unblocked]. This LED is detected by a light sensor at the end of the track, and this sensor on the track can be wired to the LabPro.
This second mechanism is a clever way to have a photogate on the cart without needing a wire going to our cart, since such a wire would cause unwanted friction. This allows us to plot the motion of the cart, as usual with a picket fence setup.
The track and carts are also designed to allow string to be wired from the cart over a pulley on the end of the track to the ground, or to have a spring between the cart and the end of the air track.
The track also has a ruler on the side of it (which will hopefully, but not necessarily, be the side facing you), so you can accurately measure positions of stationary objects on the track.
For more information, see this document.
These are designed to measure the thickness of an object or gap. They can measure in either metric or imperial units; we will, of course, use only the metric part.
An object is measured by placing it in the mouth of the calipers, and closing until the object is clamped. A gap is measured by using the "back" of the calipers: this part is placed into the gaps, and the calipers are expanded until they match the gap.
With this done, see where the zero on the calipers lines up with the scale (on the "cm" side); this will tell you the measurement down to the nearest millimeter (similar to a meter stick).
Thanks to the Vernier scale, you can read one more digit. See which mark on the sliding bit lines up with a mark on the main scale; this mark tells you how many tenths of a mm to measure.
For instance: you might read the main scale as being just under 5.7cm. If the 8 on the side scale lines up, then you would measure this as 5.68cm.
For more information, see this document.
These are used to heat water to a boiling temperature. Their operation is straightforward.
Fill the main container with water. Plug in the baseplate. Press the switch on the base to turn on the kettle.
The kettle will then heat the water. You can turn it off yourself, or it will automatically turn off if left on for too long.
For obvious reasons, do not touch the inside of the kettle while it is running.
The oscilloscope is the most complicated piece of equipment we use in our lab, and any reasonably-concise explanation will leave out some details. As such, it is important that you make the most of the lab dedicated to understanding its use.
In short, an oscilloscope makes a plot of voltage versus time, where the voltage is detected as an input signal (CH1 or CH2).
The interface of the oscilloscope is filled with options, many of which are designed to edit how this plot is displayed: the position of the plot on the screen, the x and y axis scales, etc.
The basic picture you should have is the following: a dot moves across the screen, from left to right. As it does so, it moves up when the voltage is high and down when the voltage is low. If the dot moves quickly enough (which it will, for our signals of interest), it appears to turn into a line.
The key subtlety behind the oscilloscope is triggering. Ideally, if we input a periodic signal (say, a sine wave), then we want to see that signal, traced out again and again, so that we see a stable "picture" on our screen.
This only works if each time the signal appears, looks the same. For a sine wave, this is true only if we start our plot at the same point on the signal every time we start a new sweep across the screen.
This is essentially the role of the trigger: it says "start scanning when the voltage is at this point" (and moving [up/down]). This ensures we start at the same point on the sine wave (or whatever other signal) each time.
A final thing worth noting is that the oscilloscope actually has two inputs. It can plot either one of these inputs or both simultaneously, and can trigger off of either one. (It also has a third input - EXT - which can only serve as a trigger, but we won't use that.)
There is a lot more complexity to this device, but abstractly, those are the basic principles on which it operates.
For more information, see this document, or the dedicated labs in PHY122 or PHY134.
We have several power supplies which each serve a slightly different role in our experiments.
The simplest power supply is our black box power supply. You plug it in and turn it on, and it outputs a fixed voltage. You can set this voltage to any of the settings the knob allows: 3V, 4.5V, 6V, 7.5V, 9V, or 12V.
Some experiments require a continuous range of values of voltage, rather than just a few, and we have several power supplies that can do such a thing. The simplest of these is our green box power supply, which operates similarly to our black box: you turn it on and set a voltage. (The only way to know what voltage it is outputting is to measure it.)
The remaining power supplies have an additional complexity: separate current and voltage controls. These allow you to set a maximum voltage and current simultaneously, and it will increase its output until either the voltage or current maximum are met.
They also have separate "coarse" and "fine" knobs. The idea here is that you can set an approximate value with the "coarse" knob, then adjust the voltage with the "fine" knob.
One power supply with this configuration is brown with a meter on the front, and has two knobs (coarse and fine) for voltage and one for current. It has three inputs on the side: two for red and black as usual, and a third for external ground. In principle, you can use the front-facing meter to measure voltage or current (based on the setting of the switch), but if we need to, we will just use a dedicated voltmeter or ammeter.
The other is green, and has two knobs for each of voltage and current, as well as a display. This display tells you which maximum is currently in use with a light, and has a pair of digital screens telling you what the voltage/current limit is, if said limit is being reached.
For more information about each of these power supplies, see this document.
We have a handful of function generators in our lab. They all serve identical roles, albeit with different levels of precision.
Their goal is to make a few particular periodic signals; in our lab, we will only have them output square waves or sine waves (of particular frequencies).
Since they all have slightly different subtleties of their use, we will go through each of them in sequence:
Instek GFG 8210 (green numbers on digital display)
This is the function generator you are most likely to run across in our lab. The output is of "middling quality": you will probably be able to observe small fluctuations in the frequency of the output.
To use this, turn it on and connect the "Output 50Ω" port to whatever you want the sine/square wave to travel across. Do not use the other port.
Use the second row to pick which kind of wave you want it to output (square/sine/triangle/etc.), and press that button.
To set the frequency, begin by pressing the button on the top row which is closest to the frequency you want to use (e.g., if you want 8kHz, press the "10k" button). This will cause the function generator to set itself up to output a wave with that order of magnitude.
Then, you adjust the frequency more specifically with the dedicated knob on the left of the device. Note this is actually two knobs in one: the "back" knob allows you to make large (coarse) adjustments, and the "front" knob allows you to make smaller (fine) adjustments.
You can read the frequency off the display. Note that it also (on the right side of that display) tells you what units it outputs, which may be Hz, kHz, or MHz.
Finally, if you need to, you can adjust the amplitude of your wave with the AMPL knob. You should (hopefully) not need to adjust any other setting.
Instek AFG 2005 (blue numbers and words on digital display)
These are the "nice" function generators: they output a fairly precise, steady signal; you should not observe any fluctuations in frequency.
To use this, turn it on and connect the "MAIN Output 50Ω" port to whatever you want the sine/square wave across. Do not use the other port.
Then (and this is a quirk unique to this function generator), press the "OUTPUT" button so it lights up. This will cause it to actually output the wave you tell it to.
To cycle its output through sine waves, square waves, and a few other options, presss the FUNC button.
To adjust frequency, press the FREQ button, then enter the frequency. Press the "Hz", "kHz" or "MHz" buttons (the gray buttons on the bottom row) to select the units on your input.
To adjust your amplitude, press the AMP button and enter your desired amplitude. Press "Vpp" button to have this be the peak-to-peak (top to bottom) voltage, or "Vrms" to have this be the RMS voltage.
Note that this amplitude assumes that it is being put across exactly 50Ω of resistance. In general, our circuits will not have this resistance, so do not trust this value!
Krohn-Hite 1000A (no digital display)
This function generator is comparatively complicated and difficult to set precisely, but still works if a rough frequency is sufficient. To determine the exact frequency (or amplitude), you need to use another device (such as an oscilloscope), since it lacks a digital display.
To use this, connect the "MAIN OUT HI" port (bottom right) to whatever you want it to output across, and turn it on.
Select the kind of function you want (sine/square/triangle) from the upper-right corner of the machine. If no button is pressed in, there will be no output.
This frequency depends on two factors: the frequency knob and the MULT value. The actual frequency the machine is outputting is the product of the value on the frequency knob and the chosen MULT (e.g., a value of 0.8 on the dial and the 10k MULT will output 8kHz).
To change the amplitude, turn the amplitude knob, just below the function buttons.
For more information on any of these function generators, see this document.
Our course will feature a variety of other circuit components, all of which are discussed here.
Wires and Connectors
The wires in this class will be banana cables: red or black cables with smooth connectors on the end. All other connectors used will be designed to hook up to these cables.
Generally, by experimental convention, red cables indicate high voltage and black cables indicate low voltage (or ground). That said, either red or black wires will work for any purpose, so don't stress about color too much.
Some of these banana cables have gotten worn out over the years and become loose. If you seem to have a bad connection, either jiggle the wire or try swapping it out for another wire.
Note (for your convenience) that the banana cables can connect directly to each other, using the ports on either the back or the side of the ends of the cables.
Some components will hook up to the wires directly, but some will require a little more interfacing. The simplest connector is an alligator clip: it is a clamp (which can connect to just about anything, but is particularly useful for loose connectors) that you slide on to the end of the wire.
The other key connector (used for the oscilloscopes and function generators) is a coaxial cable to banana cable adaptor. On the metal end, these slide onto the function generator or oscilloscope, and twist to lock into place. The front end then has the red and black terminals (hopefully); the black terminal should be on the side of the connector with a bump that says "GND" on it.
As an aside: in some experiments, we will put a 1Ω resistor directly between the two ends of this connector (to improve results). For the experiments where this is not intended, it may mess up your results, so it's something to watch out for.
Circuit Component Boards
Some experiments will use a "circuit component board": a bunch of components wired to screws on a plank of wood. You can connect alligator clips to these screws (or to the wires of the components directly), although you should make sure the clips intended to be on different components don't touch.
There are two boards we use: the "resistor board" and the "LRC board." The resistor board has three different resistors (R1, R2, and R3), a light bulb, and a diode-resistor pair. The LRC board has three resistors (of varying resistance), a 0.1μF capacitor (the large cylinder), and an inductor (the small red coil of wire with a rubber-like shell) with inductance [0.25mH?].
Components will vary in order by board, but should be correctly labelled. Do not remove the components from your board.
Sometimes, the connections between screws and components may be bad. In this case, you can improve your connection by attaching your alligator clips to the wires directly.
Capacitors
There are three kinds of capacitors (aside from those on the circuit boards) that we use in our labs.
The first two are variable capacitors: the large black decade capacitor, and the smaller gray capacitance substituter. Both allow for a variety of capacitances to be set, and work equivalently (although the smaller gray box has a larger range of potential capacitances).
The large black decade capacitor has three terminals, and we will use the red and black ones. The smaller gray box only has the two relevant ones.
The final standalone capacitor we have is a fixed capacitor of (allegedly) unknown capacitance, which looks like a metal cylinder.
Resistors
We have two variable resistors that we use in our labs: a large blue decade resistor, and a small gray resistance substitutor.
Both allow for a variety of resistances (although the resistance substituter allows for larger resistances), and have a fixed rsistance between their terminals (going either direction).
Inductors
We have three kinds of inductive coils that we use in our labs.
Two of them are coils (red or gold) with one terminal on each end. These consist of 520 turns of copper wire, and are identical aside from color.
The third is actually a pair of coils: a large coil and a small coil (although, depending on the experiment, you may only see one). The large coil allows for a choice of how many turns (500, 1000, or 1500), and the small coil has 175 turns.
The optical track is a long rail with position marks on it. It comes with various clamps that can be mounted on the rail.
Hopefully, these position marks will be facing you when you reach lab. If not, you may find it more convenient to rotate the rail (and perhaps flip it around) so you can see the markings.
The clamps have a marker that points (if the clamp and rail are oriented correctly) to the position of the clamp on the track. This allows for the measurement of the position of the object in the clamp along the track, assuming the object is centered over the mount of the clamp.
This allows us to place a sequence of optical objects (lenses, etc.) in sequence at specified positions along the rail, and measure those positions to a reasonable degree of precision.
The micrometer is a device designed to be able to measure the thickness of very small objects.
To make a measurement, you turn the micrometer until it's closed tight (but not so tight that you squeeze the object inside). Then, you look at the handle to read your measurement.
The notches on the stationary part of the handle are each 1mm apart (with half-mm measurements), and correspond to a 1mm difference in thickness. If your object is thinner than a mm, you won't see these.
You read sub-millimeter precision by seeing what mark on the spinning part of the handle aligns with the mark on the stationary part. Each mark here represents a difference of 0.01mm=10μm.
To combine them, you read the mm measurement (rounded down to the next half-mm), and add the sub-mm measurement to it. E.g., if your stationary part is between 4.5mm and 5mm, you might add 4.5mm from the stationary part of the handle to .32mm from the spinning part to get 4.82mm.
Unfortunately, our micrometers are not perfectly "zeroed" - fully closed may be off by some tens of micrometers from reading zero. We treat this as an "offset" - we close and measure zero, and then measure the difference in our final reading from this "zero-reading."
For more information, see this document.