Identifying , testing and combining Resistors

TTEC 4841 - Electrical and Electronics- Practical

25/8/2011 tuesday

start = 1.00pm finsh = 4.30pm

 In todays task we identifying , testing and combining Resistors

First thing we did which was Indentification and combining practice:

1. we had to obtain 6 resistors of different values.

• which we used the colour codes to calculate the value of the resistor
• measure the resistor value with a multimeter.
  

  band colour and calculations	measure value ( multimeter reading)	low tolerance value	high tolerance value	pass of fail
  82*1=82 ohms	81.4 ohms	77.9 ohms	86.1 ohms	pass
  68*1= 68ohms	68.4 ohms	64.6 ohms	71.4 ohms	pass
  68*10,000= 680,000 ohms	670 kohms	646,000 ohms	71.4000 ohms	pass
  68*100,000=6800,000 ohms	infinity	6400,000ohms	7140,000ohms	fail
  10*100 = 1,000 ohms	993 ohms	950 ohms	1050 ohms	pass
  82*10,000 = 820,000 ohms	820 kohms	779.000 ohms	861,000 ohms	fail

  
  
  
  
  This showed us how to see the colours of resistors and can be identified by a code using colours and position of the bands.
  
  
  • Then we moved on by choosing two resistors and record their individual ohm resistance value using a multimeter.
  • Resisor 1: 81.4 ohms        resistor 2 68.4 ohms
  
  
  • Then we put two resistors togather in series  ( end to end , one right after another ) measured their combined value    1 and 2 in series = 148.6 ohms
  
  
  • Then we put two resistors togather in parallel ( connect the ends when they are side - by - side ) then measured the combined value   1 and 2 = 37.1 ohms.
  
  
  This showed us in series the resistance adds up in parallel . so the resistance is divided by two. in parallel RT is always lower than the lowest branch of resistors.