• date post

10-Jan-2016
• Category

## Documents

• view

50

9

Embed Size (px)

description

ANALOGUE ELECTRONICS. 2.1. Resistors. Resistors are components which resist the flow of electricity through a circuit for a given voltage. A resistor implements electrical resistance. Image of a resistor. Symbol of a resistor. - PowerPoint PPT Presentation

### Transcript of ANALOGUE ELECTRONICS

• Slide *

ANALOGUE ELECTRONICS.

slide

• Slide *Symbol of a resistor1a. Remember the main electrical magnitudes and find the unit for each one: Watt (W)Volts (V)Ohms ()Ampere (A)Image of a resistor2.1. Resistors.Resistors are components which resist the flow of electricity through a circuit for a given voltage. A resistor implements electrical resistance.

MagnitudeUnitVoltage (V)Electric current (I)Power (P)Electric resistance ()

slide

• Slide *Symbol of a resistor1a. Remember the main electrical magnitudes and find the unit for each one: Image of a resistor2.1. Resistors.Resistors are components which resist the flow of electricity through a circuit for a given voltage. A resistor implements electrical resistance.

MagnitudeUnitVoltage (V)Volts (V)Electric current (I)Ampere (A)Power (P)Watt (W)Electric resistance ()Ohms ()

slide

• Slide *OHMS LAW connects resistance, voltage and current in an electrical circuit.

a) Formula for finding the voltage across a resistor for a given current.

b) Formula for finding the current through a resistor for a given voltage.

[ _ ] The voltage (V) across a resistor is proportional to the current (I) passing through it, where the constant of proportionality is the resistance (R).[ _ ] When a voltage V is applied across the terminals of a resistor, a current I will flow through the resistor in direct proportion to that voltage.[ _ ] Voltage across a resistor equals the current through it multiplied by the resistance.[ _ ] Current through a resistor equals the voltage across it divided by the resistance.

1b. Which formula represents these formulations of Ohms law better, a) or b)?

slide

• Slide *OHMS LAW connects resistance, voltage and current in an electrical circuit.

a) Formula for finding the voltage across a resistor for a given current.

b) Formula for finding the current through a resistor for a given voltage.

[ a ] The voltage (V) across a resistor is proportional to the current (I) passing through it, where the constant of proportionality is the resistance (R).[ b ] When a voltage V is applied across the terminals of a resistor, a current I will flow through the resistor in direct proportion to that voltage.[ a ] Voltage across a resistor equals the current through it multiplied by the resistance.[ b ] Current through a resistor equals the voltage across it divided by the resistance.

1b. Which formula represents these formulations of Ohms law better, a) or b)?

slide

• slideSlide * 1c. Choose the right answer or answers.The higher the resistance, the lower the current.The higher the resistance, the higher the current.The lower the resistance, the higher the current.The lower the resistance, the lower the current.

slide

• slideSlide * 1c. Choose the right answer or answers.The higher the resistance, the lower the current.The higher the resistance, the higher the current.The lower the resistance, the higher the current.The lower the resistance, the lower the current.

slide

• slideSlide * 1d. In this circuit, R can be 0.5 , 1 or 2 . Identify which resistance corresponds to each graph. .Construct a sentence that makes sense for graph a) and one for graph b).a) The .................................................................................................................b) The ...............................................................................................................

The lowerThe higherthe resistance,the lowerthe higherthe currentthe voltagefor a givenvoltage.current.

slide

• slideSlide * 1d. In this circuit, R can be 0.5 , 1 or 2 . Identify which resistance corresponds to each graph. .Construct a sentence that makes sense for graph a) and one for graph b).a) The higher the resistance the lower the current for a given voltage.b) The higher the resistance the higher the voltage for a given current.

The lowerThe higherthe resistance,the lowerthe higherthe currentthe voltagefor a givenvoltage.current.

slide

• slideSlide *The is too small for many resistors. Then we use the MULTIPLES kilo (k) and mega (M). Sometimes, to avoid reading errors, the letters R,k and M substitute the decimal point. 4k7 = 4.7 k = 4,700 5M6 = 5.6 M = 5,600,000 3R3 = 3.3 2a. Give the value in for the following resistors.Write the answers like the example:a) 6k8 =b) 1M2 =c) 47R =d) 5R6 =5M6: five point six mega-ohms are five million six hundred thousand .a) 6k8:b) 1M2:c) 47R:d) 5R6:

slide

• slideSlide *The is too small for many resistors. Then we use the MULTIPLES kilo (k) and mega (M). Sometimes, to avoid reading errors, the letters R,k and M substitute the decimal point. 4k7 = 4.7 k = 4,700 5M6 = 5.6 M = 5,600,000 3R3 = 3.3 2a. Give the value in for the following resistors.Write the answers like the example:a) 6k8 = 6,800 b) 1M2 = 1,200,000 c) 47R = 47 d) 5R6 = 5.6 5M6: five point six mega-ohms are five million six hundred thousand .a) 6k8: six point eight kilo-ohms are six thousand eight hundred . b) 1M2: one point two mega-ohms are one million two hundred thousand .c) 47R: forty-seven .d) 5R6: five point six .

slide

• slideSlide * 2b. Now apply Ohms law to calculate the current through the resistors as in the example. When you finish, check the answers with your partner without reading their workbook. Remember: 0.001 A = 1 mA and 0.000001 A = 1Aa)What result did you get for part a)?

slide

• slideSlide * 2b. Now apply Ohms law to calculate the current through the resistors as in the example. When you finish, check the answers with your partner without reading their workbook. Remember: 0.001 A = 1 mA and 0.000001 A = 1Aa)What result did you get for part a)?

slide

• slideSlide * 2b. b)c)d)

slide

• slideSlide * 2b. b)c)d)

slide

• slideSlide *3a. Fill in the blanks looking at the table below.A lot of resistors have coloured rings on them instead of numbers. Each colour stands for a different unit: black is zero, brown is ___ , red is two; orange is three; yellow is ___; green is five; __ _ is six; violet is seven; grey is ____; white is nine, as you can see in the table below.

The first band is for tens and the second band forunits. The third band is the multiplier.

Ex.: red / violet / green stands for 2 / 7 / 00000, that is 2,700,000 .

1st colour band2nd colour bandMultiplierToleranceBlack0Black0Silverdivide by 0.01Silver10%Brown1Brown1Golddivide by 0.1Gold5%Red2Red2Blackmultiply by 1Red2%Orange3Orange3Brownmultiply by 10Yellow4Yellow4Redmultiply by 100Green5Green5Orangemultiply by 1,000Blue6Blue6Yellowmultiply by 10,000Violet7Violet7Greenmultiply by 100,000Grey8Grey8Bluemultiply by 1,000,000White9White9

slide

• slideSlide *3a. Fill in the blanks looking at the table below.A lot of resistors have coloured rings on them instead of numbers. Each colour stands for a different unit: black is zero, brown is one, red is two; orange is three; yellow is four; green is five; blue is six; violet is seven; grey is eight; white is nine, as you can see in the table below.

The first band is for tens and the second band forunits. The third band is the multiplier.

Ex.: red / violet / green stands for 2 / 7 / 00000, that is 2,700,000 .

1st colour band2nd colour bandMultiplierToleranceBlack0Black0Silverdivide by 0.01Silver10%Brown1Brown1Golddivide by 0.1Gold5%Red2Red2Blackmultiply by 1Red2%Orange3Orange3Brownmultiply by 10Yellow4Yellow4Redmultiply by 100Green5Green5Orangemultiply by 1,000Blue6Blue6Yellowmultiply by 10,000Violet7Violet7Greenmultiply by 100,000Grey8Grey8Bluemultiply by 1,000,000White9White9

slide

• slideSlide *3b. Obtain the value of these resistors:Brown / green / red:Orange / orange / brown:Green / grey / yellow:Yellow /violet / orange:

Express the previous values with M or k if possible.For example, 27000 = 27 k

slide

• slideSlide *3b. Obtain the value of these resistors:Brown / green / red: 1/5/00= 1,500 = 1.5 kOrange / orange / brown: 3/3/0= 330 Green / grey / yellow: 5/8/0000= 580,000 = 580 kYellow /violet / orange: 4/7/000= 47,000 = 47 k

Express the previous values with M or k if possible.For example, 27000 = 27 k

slide

• slideSlide *Manufacturers of the resistors cannot guarantee an exact value.The fourth band expresses the TOLERANCE in %.

Red /violet / orange //silverR =27000 10%10% of 27000 = 2700010/100=2700R = 27000 2700

Minimum value =27000-270=26730 Maximum value = 27000+270=27270

slide

• slideSlide *3c. Calculate the minimum and maximum real values for these four resistors:

ColoursValueTol. %Tol.Minimum Maximum Red /violet / orange //silver27000 10%270026,730 27,270 Brown / green / red // silverOrange / orange / brown // goldGreen / grey / yellow // silver Yellow /violet / orange // gold

slide

• slideSlide *3c. Calculate the minimum and maximum real values for these four resistors:

ColoursValueTol. %Tol.Minimum Maximum Red /violet / orange //silver27000 10%270026,730 27,270 Brown / green / red // silver1500 10%1501,350 1,650 Orange / orange / brown // gold330 5%16.5313.5 346.5 Green / grey / yellow // silver 580000 10%58000522,000 638,000 Yellow /violet / orange // gold47000 5%235044650 49,350

slide

• slideSlide *3d. Work with your partner in turns. Choose 1 resistor from the pool and write down its colours. Then you have to tell your partner the colours and he has to find out the value.- My resistor is brown, black, red.- Yes, it is. You are right- Is it 1000 ?- My resistor is

slide