Examining Currents Through Parallel Resistors

ENGR 120

Work in Teams of Two!

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

Example: 470resistor:

4 = yellow7 = violetAdd 1 zero to 47 to make 470, so 1 = brown

Now, find the 220 resistor.

So, 470 = yellow, violet, brown

I

Build the Parallel Circuit Below(measure the total current from the power source)

Vin=6V

470

220

+ -

-

-

+

+

currentmeasurement

Compute the current after you make your measurement.How close are the measured and computed results?

current flow

curre

nt flo

w

Build the Parallel Circuit Below(measure the current through the 220 resistor)

Compute the current after you make your measurement.How close are the measured and computed results?

Vin=6V

470

220

+ -

-

-

+

+

currentmeasurement

current flow

current flow

Modify the Parallel Circuit as Shown(measure the current through the 470 resistor)

Compute the current after you make your measurement.How close are the measured and computed results?

current flow

current flow

Vin=6V

470

220

+ -

-

-

+

+

currentmeasurement

Check for Conservation of Charge

~~

Kirchoff’s Current Law (KCL) – The algebraic sum of currents entering a node is zero.

Current In = Current Out

Vin=6V

470

220

+ -

-

-

+

+

I =

I =

I =

more current goes through smaller resistor

Electrons are like people – they follow the path of least resistance.

The End