1. Prefixes and Conversion

2. Prefixes and Conversions
Prefixes are used to eliminate zeros from a given value.
Conversions change the numeric value of a measurement from one prefix’s value to another prefix’s value.
“Whole values” are: VOLTS AMPS OHMS FARAD HERTZ (C.P.S.)
“Whole values” have all of the zeros or decimal places in their number value: volts amps ,000,000 ohms farads
Prefixes are added to “whole value”electrical measurements to eliminate zeros or decimal places:
3 K volts 1 K amps
5M ohms uf

3. Prefixes and their relationship to “whole values”
Prefix Symbol Move decimal pt. Value
Mega= 1,000, M places M
Kilo= 1, K places K
“whole values” Amp Volt Ohm Farad Hertz (C.P.S.)
milli= m places m
micro= u places u
nano= n places n
pico= p places p

4. Key to Remember You move in steps of 3 between prefixes
Prefixes: Symbol:
Mega = M
Kilo = K
Whole values = 0
milli = m
micro = u
nano = n
pico = p
3 steps
You move in steps of 3 between prefixes
3 steps
3 steps
3 steps

5. Converting from Whole Number
Convert the following:
5,000,000.0 ohms
Prefixes: Symbol:
Mega = M
Kilo = K
Whole values = 0
milli = m
micro = u
nano = n
pico = p
Left
Right
Which way decimal point moved
Determine how many decimal places to move from decimal point to achieve desired value (in this case 5_) 6
2. Which way would I move the decimal point to change the number ?
Left
3. What prefix will be used? M
4. Move the decimal to produce the correct answer.
5,000, =
5 M ohms
Moving decimal point left

6. Examples for class to work out
Convert the following whole numbers to the appropriate prefix which minimizes the number of zeros.
25,000,000 = ___ 256,000 = ____
12,000 = ___ 3,100,000 = ___
1,000 = ___ 780,000,000 = ___
900 = ____ 1,020,000 = ___ ____

7. Converting from Whole Number
Prefixes: Symbol:
Mega = M
Kilo = K
Whole values = 0
milli = m
micro = u
nano = n
pico = p
Left
Right
Which way decimal point moved
Convert the following: f
Determine how many decimal places to move from decimal point to achieve desired value (in this case 1_) 6
2. Which way would I move the decimal point to change the number ?
Right
3. What prefix will be used? u
4. Move the decimal to produce the correct answer.
f =
1 uf
Move decimal point right

8. Examples for class to work out
Convert the following whole numbers to the appropriate prefix which minimizes the number of zeros.
0.001 = ____ = ____
0.07 = ____ = ___
= ___ = ___
= ____ = ___

9. Changing between Prefixes
Sometimes it is desired to change between prefixes. For example:
0.5M to 500K
1.2nF to 1200pF
10000nf to 0.01uf
Why?
½ million sounds bigger than 500K.
Standard way to specify capacitors is in pF
Meters read easier with fewer numbers.

10. Prefix to Prefix Conversion
6pl
Decimal
Point
Converting from one prefix to another
Using the scale above, circle the prefix that matches the number you are starting with.
Circle the prefix you want to convert to.
Count the tick marks between the two circles to determine the number of decimal places to move.
Move the decimal point in the same direction as moving from the first circle to second circle and change the prefix letter.
Convert 1200p to _u
0.00
1200p
= u

11. Problems to work in class
Perform the following prefix to prefix conversions.
1000p = _____u 120p = ____u
0.1u = ______n 0.01u =______p
1n = _______ p 4700p =_____n
100m = _____K 1100K = _____M
4M = _____K 3G = ____M

12. Using Prefixes in Programs
Prefixes can be used in calculators and Excel.
In a Calculator, you usually have a button labeled EE or in Excel you enter “e” to represent 10 to some power. The table below are cross references on what you would enter.
No prefix Prefix Calculator Excel
1,000,000 1M 1 EE 6 1 e 6
1,000 1K 1 EE 3 1 e 3
m 1 EE e –3
u 1 EE –6 1 e –6
n 1 EE –9 1 e –9
p 1 EE e –12
Note that the number to the right of “EE’ or “e” represents how many places to move the decimal point and which way to move. A positive number mean move the decimal point to the left. A negative number means move the decimal number to the right.

13. How Prefix is applied
Meters are limited in number of digits it can display.
Prefixes are built into the meter.
The numbers on the meter show the maximum value.
If 200uA is selected, the maximum reading is 199uA
If 1 is displayed on 200u A scale, what does this mean?
1uA or A

14. Meter Problems Convert the following meter readings to whole numbers
Meter Scale Reading Whole Number
200m ____________
200u ____________
200K ____________
20K ____________
____________
20m ____________