# UK Amateur Radio ## Foundation Licence 2002
### Technical Basics Part C
### Prefixes You have learned something of the units we use to measure voltage (V), current (I), resistance (ohms ), frequency (Hz) and power (W). However, sometimes we have either a lot or a little of these and we find that working with either very large or small numbers difficult. This is the same as you have with money, a new car may cost you £10,000 but you do not refer to its price in pennies (which would be 1,000,000 pence) because it is harder to work with. Similarly, you refer to refer to the price of very cheap things in pennies - you don't ask in a sweet shop for a 1/100 of a £1 chew ! We use this same trick in electronics but is a slightly different way. If we have 1000 of something we use the letter k (note 'small' k) for kilo to indicate thousands. If we have 1,000,000 of something we use the letter M for Mega to indicate millions. If we only have 1/1000 of something we use the letter m (note 'small' m) for milli to indicate one thousandth We call these letters 'prefixes'. There is a graphic below to help you remember the relative sizes of these prefixes.
### milli kilo and Mega There are many prefixes used in the amateur radio circuits but for the Foundation Licence you only have to know :-
###  | ###  | ###
Now trying to remember these is not easy but its is hopes the graphics will be of some help.
| m - the small bug the millipede smaller than one
| number one is where we start from
| k - bigger than one but less than Mega
| M but the biggest of all. We often talk of mega bucks meaning loads of money and a mega burger meaning a very large burger
You may have already heard of a kilo in its part that it plays as a kilogram which is 1000 grams well in electrical theory the kilo is use the same way. 1kv = 1000 volts 1k = 1000 or 1000ohms also written as 1k0 going bigger we have the Mega which is 1000 times bigger AGAIN !!! 1Mv = 1 000 000 volts 1M = 1 000 000 And then we go smaller than ONE 1 mV = 1 milli volt or 0.001 volts 1 mA = 1 milli amp or 0.001 amps
### Summary
0.001 | m milli
1 | no prefix just a normal number !!
1 000 | k kilo
1 000 000 | M Mega

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