physics 2025: working with electronic equipment purpose learn how to use basic electronic...
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Physics 2025: Working With Electronic Equipment
PurposeLearn how to use basic electronic
equipment:• Digital multi meter • Oscilloscope • Function generator• Bread board
Apply and verify Ohm’s laws.
Physics 2025: Working With Electronic Equipment
Digital Multi Meter (“DMM”)
A DMM is a device to measure• voltage,• current,• resistance,• and more….depending on the model
There are two modes to measure voltage and current:•“AC” (alternating current)•“DC” (direct current)
You need to know whether you are measuring an “AC” or “DC” current/voltage and set your DMM accordingly. Otherwise your measurement is wrong.
Note: We use the term “DC” or “AC” also for voltages, even thoughThe “C” stands for “Current” (Example: 5V DC).
Physics 2025: Working With Electronic Equipment
Measuring AC with a DMMV or I
time
AC
If you measure this AC voltage/current in the “DC” mode, the result is the average (averaged over time) value (in this case zero).
average value
If you measure this AC voltage/current in the “AC” mode, the result is the the peak value divided by (assuming a sinusoidal oscillation around zero).2
AA
A707.0
2
Always measure AC in the AC mode.
Physics 2025: Working With Electronic Equipment
Measuring DC with a DMM
V or I
time
DC
If you measure this voltage/current in the “DC” mode, the result is the average (averaged over time) value, which equals the DC value.
average value
Always measure DC in the DC mode.
Physics 2025: Working With Electronic Equipment
Setting AC or DC on DMM (Fluke 87)
DC voltage
AC voltage
Current:Switch betweenDC and AC bypushing theblue button.
Physics 2025: Working With Electronic Equipment
Setting AC or DC on DMM (MultiTec 320)
Voltage:Put dial to “V”.Switch betweenDC and AC bypushing theDC/AC button.
Current:Put dial to mA or A.Switch betweenDC and AC bypushing theDC/AC button.
Physics 2025: Working With Electronic Equipment
Measuring a Voltage with the DMMVoltmeters have very high resistance. Very little current will flow through a voltmeter even if V is high. It is hard to damage a voltmeter.
Voltmeters are connected “in parallel” to measure the voltagebetween two points.
0.003
COM V
V
Resistor
5 V
GND = 0 V
current
A very tiny amount of current (ideally almost zero) goes through the voltmeter.
Important: Use COM (ground) and V ports for voltage measurement!
Physics 2025: Working With Electronic Equipment
Measuring a Current with the DMM
Current meters (“amp meters”) have very low resistance. When hooked up to an even small voltage difference, a large current would flow through a current meter. It would be easy to damage a current meter. Current meters are protected by a fuse (if you blow the fuse the current meter will no longer work until the fuse is replaced).
Amp meters are connected “in series” to measure the current in a circuit.
0.003
COM V
A Resistor
5 V
GND = 0 V
current
Important: Use COM (ground) and mA or A (large currents) ports for current measurement!
mA
Physics 2025: Working With Electronic Equipment
NEVER DO THIS !!!!!!!!!!!!!!!!!!!!!!!!!!!
0.003
COM V
A Resistor
5 V
GND = 0 V
huge current
Because the amp meter has almost no resistance, it gives the electrons an easy path between 5V and ground. Huge current through amp meter will blow the fuse.
A
Fuse will blow out !!!
Physics 2025: Working With Electronic Equipment
The Correct Way, Again
0.003
COM V
A Resistor
5 V
GND = 0 V
current
NoticeIf you follow the path of the current you can see that it is forced to go through the resistor,which limits its current (by Ohm’s law….Current = Voltage / Resistance).
mA
Physics 2025: Working With Electronic Equipment
The Function Generator
• Time-varying voltage/current.• Three different wave shapes (sinusoidal, square, triangular).• Variable frequency.• Variable amplitude of the signal.• DC offset of signal.
Physics 2025: Working With Electronic Equipment
The Function Generator – Wave Shape Selection
Sinusoidal Wave
Square Wave
Triangular (“Sawtooth”)Wave
Physics 2025: Working With Electronic Equipment
The Function Generator – Frequency Range
Up to 5 Hz
Up to 50 Hz
Up to 500 Hz
Within each range you can vary the frequency (see next slide).
Physics 2025: Working With Electronic Equipment
The Function Generator – Frequency Variation
Coarse regulation
Fine regulation
Display of frequency:For low frequenciesyou need to wait a few seconds for the correctvalue to show (it takestime to measure it).
Physics 2025: Working With Electronic Equipment
The Function Generator – Output Level
Signal output: Connect BNC cable here.
Adjust the amplitudeof the signal at “Output Level”.
Physics 2025: Working With Electronic Equipment
What is “DC Offset” ?
0 VoltNo “DC offset”
0 Volt
2 Volt
Signal has “DC offset”of + 2 Volts (the signal fluctuates around +2 V instead of 0 V).
Physics 2025: Working With Electronic Equipment
The Function Generator – Generating a “DC Offset”
Push “DC OFFSET”Button IN to enableDC offset adjustments.
Adjust the amount ofDC offset here.
Physics 2025: Working With Electronic Equipment
The Heathkit “Bread Board”
Called “Bread Board” because you can use itto “breed” electriccircuits.
The board allows you to test your circuitsbefore you build apermanent version.
Physics 2025: Working With Electronic Equipment
The Heathkit “Bread Board” – the Actual “Board”
This is the board:
Makes connecting electric components(resistors, capacitors,integrated circuits…)EASY.
Physics 2025: Working With Electronic Equipment
How the “Holes” are Connected
5 holes in a“column” areelectricallyconnected.
But:Red and Greenare NOT connectedacross the center break.
The center break
Physics 2025: Working With Electronic Equipment
How the “Holes” are NOT Connected
Holes in a“row” areelectricallyNOT connected.
Physics 2025: Working With Electronic Equipment
How the “Holes” are NOT Connected
Top break
Holes are NOT connectedacross the top break.
Note: Many of our bread boards do not have the double row above the top break any more.
Physics 2025: Working With Electronic Equipment
Power Supply to the Bread Board
Main Power: Switches all voltagesON or OFF.
GND = 0 Volts (“Ground”)
Example:To get 5 Volts:Use GND and +5
Physics 2025: Working With Electronic Equipment
Example of Setting up a Simple Circuit
Resistor
5 V
GND
5VR Circuit Diagram
A more pictorial view of thesame circuit.
Physics 2025: Working With Electronic Equipment
And How it Looks on the Bread Board
Physics 2025: Working With Electronic Equipment
And from Another Angle…..
Notice, how wetake advantageof the hidden connections between theholes in acolumn.
Physics 2025: Working With Electronic Equipment
Binary Numbers
In digital electronics information is coded as binary numbers whichcontain only Ones and Zeroes.
Example: 1001 (binary) = 1x23+0x22+0x21+1x20 = 9 (decimal)
Any decimal number can be converted to a binary number and storedelectronically (e.g., in a computer).
1’s and 0’s are often stored as High (5Volt) and Low (0 Volt) voltages.
For example, the number shown above (1001) could be represented by 4 “data lines” that have either high or low voltages.
5V 5V0V 0V
1 0 0 1
Physics 2025: Working With Electronic Equipment
Data Switches, Logic Indicators
The bread board has “Data Switches” providing “High” and “Low” voltage for digital logic .
The bread board also has LEDs (Light Emitting Diodes) which act as logic indicators (a quick way to find out whether a voltage is “High” or “Low”).
Switch
Output(low or high)
5V (SW2 up)
0V (SW4 down)
Physics 2025: Working With Electronic Equipment
Resistor Color Code
Our resistors have 4 colored bands on them. See your manual for color code.
Gold = 5% uncertainty
First bandRed = 2
Second bandBlack = 0
Third bandBrown = Multiplier 10 W
Resistance = 2 0 * 10 W = 200 W 10 W
Physics 2025: Working With Electronic Equipment
The OscilloscopeA device to display a voltage as a function of time (useful for voltages that vary with time – e.g. oscillating signals). You can display 2 signals simultaneouslyusing the two input channels (Ch.1 and 2).
time
Voltage
Channel 1 input Channel 2 input
Physics 2025: Working With Electronic Equipment
Changing the Horizontal (Time) Scale
Change horizontaltime scale here.
Physics 2025: Working With Electronic Equipment
Changing the Vertical Scale on Channel 1
Change the verticalscale here.
For more optionson how to usechannel 1 pressthe MENU button.
The little knob shifts the signalup or down (unlessthe cursor is used).
Physics 2025: Working With Electronic Equipment
Using the Cursor
Press the CURSORbutton to enable thecursors.
Once the cursorbutton is pushedthese two knobsmove the twocursors.
Physics 2025: Working With Electronic Equipment
Using the Cursor
Change the type ofcursor betweenvoltage cursor ortime cursor with thisbutton.
Indicates voltage atwhich cursors 1 and2 are.
Indicates voltagedifference betweencursor 1 and 2.
Physics 2025: Working With Electronic Equipment
Time Cursor Selected
The two timecursors.
Physics 2025: Working With Electronic Equipment
Connectors and Their Names
“BNC” cable
“Shield”
Center pin
A BNC cable is basically a double cable:One “cable” is the center conductor ending in the center pin.The other “cable” is the “shield”. A BNC cable can do the job of two parallel wires.
Physics 2025: Working With Electronic Equipment
An Adaptor Used in this Lab
Adapter: BNC (female)to Banana (male)
“Ground” indicator:Indicates that this sideof the banana end connectsto the “Shield” of the BNCconnector.The other banana end connectsto the center conductor of theBNC.
Physics 2025: Working With Electronic Equipment
Suggestion for Using Cables and DMM
BNC small clips easilyattach to resistors etc.
Use adapter to plug into DMM
The “Ground” plugon the BNC/Bananaadapter connects tothe small black clip.
Physics 2025: Working With Electronic Equipment
More…..
• More and different types of cables can be throughout room 405 hanging on the walls.
• There are also more and other types of adapters in the brown cabinet labeled “L” to the left of the entrance or they may be on the shared table.
• Should – against all warnings – you blow a fuse on yourDMM, ask your TA for a replacement.
Physics 2025: Working With Electronic Equipment
Checking Fuse on Mutitec320 DMM is Easy
Just dial to “mA” and the display should look like this.
This symbol indicates a broken fuse.
Other types of DMMshave no indicator.
Physics 2025: Working With Electronic Equipment
Wires
Special Wires: Do not cut !
Physics 2025: Working With Electronic Equipment
Banana Leads fit to DMM Ports
Black wire: COM (convention)
Use COM and V ports for voltage and resistance measurements
Physics 2025: Working With Electronic Equipment
Microclips
Physics 2025: Working With Electronic Equipment
BNC - Banana Adapter
Physics 2025: Working With Electronic Equipment
Completing a Circuit
Measuring Voltage with Microclips
Physics 2025: Working With Electronic Equipment
Measuring Current
Physics 2025: Working With Electronic Equipment
Resistors in Series
Physics 2025: Working With Electronic Equipment
Parallel Resistors - Measuring Current in Main Branch
Physics 2025: Working With Electronic Equipment
Please put the special cables neatly back into the blue boxes !