1. Purpose Learn how to use basic electronic equipment:
Digital multi meter
Oscilloscope
Function generator
Bread board
Apply and verify Ohm’s laws.

2. 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)
Note: We use the term “DC” or “AC” also for voltages, even though
The “C” stands for “Current” (Example: 5V DC).
You need to know whether you are measuring an “AC” or “DC” current/voltage and set your DMM accordingly. Otherwise your measurement is wrong.

3. AC Measuring AC with a DMM V or I time
average value
time
If you measure this AC voltage/current in the “DC” mode, the result is the
average (averaged over time) value (in this case zero).
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).
 Always measure AC in the AC mode.

4. DC Measuring DC with a DMM V or I time
average value
time
If you measure this voltage/current in the “DC” mode, the result is the
average (averaged over time) value, which equals the DC value.
 Always measure DC in the DC mode.

5. Setting AC or DC on DMM (Fluke 87)
Current:
Switch between
DC and AC by
pushing the
blue button.
DC voltage
AC voltage

6. Setting AC or DC on DMM (MultiTec 320)
Current:
Put dial to mA or A.
Switch between
DC and AC by
pushing the
DC/AC button.
Voltage:
Put dial to “V”.
Switch between
DC and AC by
pushing the
DC/AC button.

7. Measuring a Voltage with the DMM
Voltmeters 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 voltage
between two points.
A very tiny amount of current
(ideally almost zero) goes
through the voltmeter.
5 V
0.003
current
Resistor
GND
= 0 V V
COM V
Important: Use COM (ground) and V ports for voltage measurement!

8. 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.
5 V
current
0.003
Resistor A
GND
= 0 V mA
COM V
Important: Use COM (ground) and mA or A (large currents) ports for current measurement!

9. NEVER DO THIS !!!!!!!!!!!!!!!!!!!!!!!!!!! 5 V huge current 0.003
Resistor A
GND
= 0 V A
COM V
Fuse will blow out !!!
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.

10. The Correct Way, Again 5 V current 0.003 Resistor GND = 0 V NoticemA
COM V
Notice
If 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).

11. 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.

12. The Function Generator – Wave Shape Selection
Sinusoidal Wave
Square Wave
Triangular
(“Sawtooth”)
Wave

13. The Function Generator – Frequency Range
Within each range you can vary the frequency (see next slide).
Up to 5 Hz
Up to 50 Hz
Up to 500 Hz

14. The Function Generator – Frequency Variation
Display of frequency:
For low frequencies
you need to wait a few
seconds for the correct
value to show (it takes
time to measure it).
Coarse regulation
Fine regulation

15. The Function Generator – Output Level
Adjust the amplitude
of the signal at
“Output Level”.
Signal output: Connect
BNC cable here.

16. What is “DC Offset” ? No “DC offset” 0 Volt Signal has “DC offset”
of + 2 Volts (the signal
fluctuates around
+2 V instead of 0 V).
2 Volt
0 Volt

17. The Function Generator – Generating a “DC Offset”
Push “DC OFFSET”
Button IN to enable
DC offset adjustments.
Adjust the amount of
DC offset here.

18. The Heathkit “Bread Board”
Called “Bread Board”
because you can use it
to “breed” electric
circuits.
The board allows you
to test your circuits
before you build a
permanent version.

19. The Heathkit “Bread Board” – the Actual “Board”
This is the board:
Makes connecting
electric components
(resistors, capacitors,
integrated circuits…)
EASY.

20. How the “Holes” are Connected
5 holes in a
“column” are
electrically
connected.
But:
Red and Green
are NOT connected
across the center break.
The center break

21. How the “Holes” are NOT Connected
Holes in a
“row” are
electrically
NOT connected.

22. How the “Holes” are NOT Connected
Top break
Holes are NOT connected
across the top break.
Note: Many of our bread boards do not have the double row above the top break any more.

23. Power Supply to the Bread Board
Main Power: Switches all voltages
ON or OFF.
GND = 0 Volts (“Ground”)
Example:
To get 5 Volts:
Use GND and +5

24. Example of Setting up a Simple Circuit
Circuit Diagram 5V
Resistor
5 V
GND
A more pictorial view of the
same circuit.

25. And How it Looks on the Bread Board

26. And from Another Angle…..
Notice, how we
take advantage
of the hidden
connections
between the
holes in a
column.

27. Binary Numbers
In digital electronics information is coded as binary numbers which
contain only Ones and Zeroes.
Example: (binary) = 1x23+0x22+0x21+1x20 = 9 (decimal)
Any decimal number can be converted to a binary number and stored
electronically (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 0V 0V 5V

28. Data Switches, Logic Indicators
The bread board has “Data Switches” providing “High” and “Low” voltage for digital logic .
Switch
Output
(low or high)
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”). 0V
(SW4 down) 5V
(SW2 up)

29. Resistor Color Code Gold = 5% uncertainty First band Second band
Our resistors have 4 colored bands on them. See your manual for color code.
Gold = 5% uncertainty
First band
Red = 2
Second band
Black = 0
Third band
Brown = Multiplier 10 W
Resistance = 2 0 * 10 W = 200 W  10 W

30. The Oscilloscope Voltage time
A 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 simultaneously
using the two input channels (Ch.1 and 2).
Voltage
time
Channel 1 input
Channel 2 input

31. Changing the Horizontal (Time) Scale
Change horizontal
time scale here.

32. Changing the Vertical Scale on Channel 1
The little knob
shifts the signal
up or down (unless
the cursor is used).
For more options
on how to use
channel 1 press
the MENU button.
Change the vertical
scale here.

33. Using the Cursor Press the CURSOR button to enable the cursors.
Once the cursor
button is pushed
these two knobs
move the two
cursors.

34. Using the Cursor Change the type of cursor between voltage cursor or
time cursor with this
button.
Indicates voltage
difference between
cursor 1 and 2.
Indicates voltage at
which cursors 1 and
2 are.

35. Time Cursor Selected
The two time
cursors.

36. Connectors and Their Names
Center pin
“BNC” cable
“Shield”
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.

37. An Adaptor Used in this Lab
Adapter:
BNC (female)
to Banana (male)
“Ground” indicator:
Indicates that this side
of the banana end connects
to the “Shield” of the BNC
connector.
The other banana end connects
to the center conductor of the
BNC.

38. Suggestion for Using Cables and DMM
BNC
small clips easily
attach to resistors etc.
The “Ground” plug
on the BNC/Banana
adapter connects to
the small black clip.
Use adapter to plug into DMM

39. 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 your
DMM, ask your TA for a replacement.

40. 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 DMMs
have no indicator.

41. Special Wires: Do not cut !

42. Banana Leads fit to DMM Ports
Use COM and V ports for voltage and resistance measurements
Black wire: COM (convention)

43. Microclips

44. BNC - Banana Adapter

45. Measuring Voltage with Microclips
Completing a Circuit
Measuring Voltage with Microclips

46. Measuring Current

47. Resistors in Series

48. Parallel Resistors - Measuring Current in Main Branch

49. Please put the special cables neatly back into the blue boxes !