breadboards multimeters and resistors n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Breadboards, Multimeters, and Resistors PowerPoint Presentation
Download Presentation
Breadboards, Multimeters, and Resistors

Loading in 2 Seconds...

play fullscreen
1 / 16

Breadboards, Multimeters, and Resistors - PowerPoint PPT Presentation


  • 91 Views
  • Uploaded on

Breadboards, Multimeters, and Resistors. EGR1301. Your Multimeter. pincer clips – good for working with Boe-Bot wiring. probes. (push these onto probes). leads. turn knob to what you would like to measure. You will use the multimeter to understand and troubleshoot circuits, mostly

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Breadboards, Multimeters, and Resistors' - tod


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
your multimeter
Your Multimeter

pincer clips – good for working

with Boe-Bot wiring

probes

(push these onto probes)

leads

turn knob to what you

would like to measure

You will use the multimeter to understand and troubleshoot circuits, mostly

measuring DC voltage, resistance and DC current.

slide3

Measure Vin

Vin will be the same as your power supply voltage. For the case below, 4 AA

batteries are used resulting in approximately 6 V (5.79 V to be more exact).

Vin = power supply voltage

Vss = ground (negative side of battery)

Switch to DC Volts

slide4

Measure Vdd

Vdd will always be around 5V (it is 4.94 V here). A voltage regulator on the

Board of Education reduces this voltage from Vin down to ~ 5V. The Boe-Bot

operates on 5V DC.

Vdd ~ 5V

Vss = ground (negative side of battery)

slide5

Build the Series Circuit Below

5V

+

-

220W

470W

the breadboard connects

these resistors

slide6

Select Resistors

Find the 220W and the 470W resistors from your Boe-Bot kit.

Example: 470W resistor:

4 = yellow

7 = violet

Add 1 zero to 47 to make 470, so 1 = brown

So, 470 = yellow, violet, brown

Now, find the 220W resistor.

slide7

Check Resistance of Resistors

R ~ 470W

set multimeter

to measure W

slide8

Compute the Voltage Drops Across the Two Resistors

(Hint: compute the total current provided by the power source

and then apply Ohm’s Law to each resistor)

5V

+

-

DV = 3.41V

220W

470W

SOLUTION:

DV = 1.59V

Now, add the voltage rise of

the power source (+5V) to the

voltage drops across the resistors

(negative numbers).

5V – 3.41V – 1.59V = 0

your multimeter1
Your Multimeter

pincer clips – good for working

with Boe-Bot wiring

probes

(push these onto probes)

leads

turn knob to what you

would like to measure

You will use the multimeter to understand and troubleshoot circuits, mostly

measuring DC voltage, resistance and DC current.

slide10

Use Multimeter to Measure Voltages Around Loop

(1) From Vdd to Vss

DV1 = _____

(2) Across the 470W resistor

DV2 = _____

Remember . . .

a RESISTOR is a voltage DROP and

a POWER SOURCE is a voltage RISE

DV1 - DV2 - DV3 = ________

(3) Across the 220W resistor

DV3 = _____

Rises must balance drops!!!!

slide11

Compare Measurements to Theory

DV = 3.41V

DV = 1.59V

Pretty close!

slide12

Kirchoff’s Voltage Law (KVL)

Kirchoff’s Voltage Law says that the algebraic

sum of voltages around any closed loop in a

circuit is zero – we see that this is true for our

circuit. It is also true for very complex circuits.

DV = 3.41V

5V – 3.41V – 1.59V = 0

DV = 1.59V

Notice that the 5V is DIVIDED between the two resistors, with the larger voltage drop occurring

across the larger resistor.

slide13

Gustav Kirchoff (1824 – 1887) was a German physicist who made fundamental contributions to the understanding of electrical circuits and to the science of emission spectroscopy. He showed that when elements were heated to incandescence, they produce a characteristic signature allowing them to be identified. He wrote the laws for closed electric circuits in 1845 when he was a 21 year-old student.

Photo: Library of Congress

slide14

Connecting an LED

LED = Light Emitting Diode

Diagram from the Parallax Robotics book

Electricity can only flow one way through an LED (or any diode).

slide15

Building an LED Circuit

Vdd =

LED

These circuit diagrams

are equivalent

these holes are “connected”

Vdd = 5V

holes in this direction are not connected

Diagram from the Parallax Robotics book

slide16

Replace the 470W Resistor

with the 10kW Resistor

What happens and Why??

ANSWER: The smaller resistor (470W) provides less resistance to current than

the larger resistor (10kW). Since more current passes through the smaller

resistor, more current also passes through the LED making it brighter.

What would happen if you forgot to put in a resistor? You would probably burn

up your LED.