Understanding Electronics Units and Prefixes
Learn about the basic units used in electronics and how prefixes and standard form can simplify working with large and small numbers. Explore the standard quantities like current, voltage, resistance, energy, power, time, frequency, and capacitance. Discover how prefixes like milli, micro, and nano are used for small quantities to express values conveniently in electronics.
Download Presentation
Please find below an Image/Link to download the presentation.
The content on the website is provided AS IS for your information and personal use only. It may not be sold, licensed, or shared on other websites without obtaining consent from the author. If you encounter any issues during the download, it is possible that the publisher has removed the file from their server.
You are allowed to download the files provided on this website for personal or commercial use, subject to the condition that they are used lawfully. All files are the property of their respective owners.
The content on the website is provided AS IS for your information and personal use only. It may not be sold, licensed, or shared on other websites without obtaining consent from the author.
E N D
Presentation Transcript
Units & Prefixes AIM: To learn the basic units used in electronics and to understand how prefixes and standard form can be used to make large and small numbers easier to work with. PRIOR KNOWLEDGE: Basic maths powers of 10, standard form www.pfnicholls.com
Quantities & Units The standard quantities and their associated units are: Current (I) measured in amperes (A) E.g. A kettle takes a current of 12 A Voltage (V) measured in volts (V) E.g. We use a 9 V battery Resistance (R) measured in ohms ( ) E.g. An LED needs a 470 series resistor
Quantities & Units The standard quantities and their associated units are: Energy (E) measured in joules (J) E.g. In 10 minutes the bulb dissipates 1000 J on energy Power (P) measured in watts (W) E.g. Using 100 J per second is a power of 100 W Charge (Q) measured in coulombs (C) E.g. In 5 minutes a charge of 20 C flows through the bulb
Quantities & Units The standard quantities and their associated units are: Time (t) measured in seconds (s) E.g. The circuit remained on for 20 s Frequency (f) measured in hertz (Hz) E.g. The astable circuit had a frequency of 25 Hz Capacitance (C) measured in farads (F) E.g. The circuit needed a 0.01 F capacitor
Prefixes for small quantities m Prefix Milli Symbol m 1000 10-3 Prefix meaning Standard form A current of 5 mA in standard units is 5 1000 = 0.005 A A power of 200 mW in standard units is 200 1000 = 0.2 W A voltage of 0.04 V in more convenient units is 0.04 1000 = 40 mV
Prefixes for small quantities Prefix Micro 1000,000 10-6 Symbol Prefix meaning Standard form A current of 5 A in standard units is 5 1000,000 = 0.000005 A A power of 2000 W in standard units is 2000 1000,000 = 0.002 W which is is also 2 mW because 1000 W = 1 mW Capacitance of 100 F in standard units is 100 1000,000 = 0.0001 F In the above examples, 5 A is more conveniently written as 5 10-6 A and 100 F as 100 10-6 F
Prefixes for small quantities n Prefix Nano Symbol n 1000,000,000 10-9 Prefix meaning Standard form A current of 5 nA is 5 1000,000,000 = 0.000000005 A which is really inconvenient to write down so it should always be written as 5 10-9 A Power of 2000 nW in standard units is 2000 1000,000,000 = 0.000002 W which is is also 2 W because 1000 nW = 1 W Capacitance of 47nF in standard units is 47 1000,000,000 = 0.000000047 F which is too inconvenient so it should always be written as 47 10-9 F
Prefixes for small quantities p Prefix Pico Symbol p 1000,000,000,000 10-12 Prefix meaning Standard form Pico is a really small quantity and is really only used for capacitance A capacitance of 33 pF in standard units is 33 1000,000,000,000 = 0.000000000033 F which is too inconvenient. It should always be written as 33 10-12 F 56 nF = 56,000 pF because 1 nF = 1000 pF 470 pF = 0.47 nF because 1 pF = 0.001 nF
Prefixes for large quantities k Prefix Kilo Symbol k 1000 103 Prefix meaning Standard form A current of 5 kA in standard units is 5 1000 = 5000 A A resistance of 68 k in standard units is 68 1000 = 68,000 A voltage of 2400 V in more convenient units is 2400 1000 = 2.4 kV
Prefixes for large quantities M Prefix Mega Symbol M 1000,000 106 Prefix meaning Standard form A current of 5 MA in standard units is 5 1000,000 = 5000,000 A A resistance of 1.2 M is 1.2 1000,000 = 1,200,000 A power of 6,000,000 W in more convenient units is 6 MW
Prefixes for large quantities G Prefix Giga Symbol G 1000,000,000 109 Prefix meaning Standard form A frequency of 2.4 GHz in standard units is 2.4 1000,000,000 = 2400,000,000 Hz. This is not a convenient number to write out so it would be written as 2.4 109 Hz A resistance of 0.2 G is written as 200 M because 1 G = 1000 M
Prefixes for large quantities T Prefix Tera Symbol T 1000,000,000,000 1012 Prefix meaning Standard form Tera is a very large prefix and is really only applied to very high frequencies (THz) or large amounts of bytes of data (TB) in hard drives in computer systems A frequency of 4 THz in standard units is 4 1000,000,000,000 = 4000,000,000,000 Hz. This is not a convenient number to write out so it would be written as 4 1012 Hz
Summary Quantities and Units
Summary Working with small numbers
Summary Working with large numbers
Questions 1. What is 7 mA in standard units of amperes? 2. What is 0.00004 V in a more convenient form? 3. What is 56 J in standard form? 4. What is 47 F in standard form? Or in standard units? 5. What is 27 nF in F? 6. What is 0.1 F in nF? 7. What is 5 ms in standard form and in standard units of seconds? 8. What is 0.2 s in ms?
Answers 1. 7 mA = 0.007 A (divide by 1000) 2. 0.00004 V = 0.04 mV or 40 V or 40 x 10-6 V or 4 x 10-5 V 3. 56 J = 56 x 10-6 J 4. 47 F = 47 x 10-6 F or 0.000047 F 5. 27 nF = 0.027 F (divide by 1000) 6. 0.1 F = 100 nF (multiply by 1000) 7. 5 ms = 5 x 10-3 s or 0.005 s 8. 0.2 s = 200 ms (multiply by 1000)
