EXPERIMENT No.1

EXPERIMENT No. 1

Identifying, Testing and Troubleshooting Semiconductor Components

Identifying, Testing and Combining Resistors

First two or three bands may be the numbers to write down Next band is the multiplier (how many zeros to add to the number) Gold multiplier makes one decimal place smaller, Silver makes two decimal places smaller Last band to right may be tolerance values Notice the examples on the right Brown, red, red = 1, 2, 100, 5% = 1200Ω 5%, or 1.2KΩ,1K2

      

 Obtain 6 resistors of different values.  You are then going to determine their value two ways: 

·      Use the colour code to calculate the value of the resistor.

·      Include the maximum and minimum tolerance value of each resistor

·      Then measure the resistor value with a multimeter.

Record the values in the chart below:

Value (colour codes )	Value (multimeter)
10,000 x 0.05= 500 -9,500     +10,500	9.96kW
5600 x 0.05= 280 -5320      +5880	5.548kW
4700 x 0.01= 47 -4653      +4747	472.1W
100,000 x 0.05= 5000 -95000     +105000	99.3kW
270 x 0.05= 13.5 -256.5      +283.5	269.0W
100 x 0.05= 5 -95           +105	98.9W

Choose two resistors and record their individual ohm resistance value measured with a multi-meter:

            Resistor 1. 269.1Ω      Resistor 2. 471.9Ω

Put these two resistors together in series (end to end, one right after another) calculate and then measure their combined value. Show workings:

Calculated value 1 and 2 in series: Rt = R1 + R2 = 472.1 + 269.0

                                                         Rt = 741.1

Measured value 1 and 2 in series: 739kΩ

Put these two resistors together in parallel (connect both ends when they are side-by-side). Calculate and then measure their combined value. Show workings:

                                                                                                  

Calculated value 1 and 2 in parallel: 1/Rt = 1/R1 + 1/R2 = 1/269.1 + 1/471.9

                                                           Rt = 471.9 x 269.1 = 126988.29

                                                                 ____________   ________

                                                                  269.1 + 471.9 =     741

                                                           Rt = 171.3

                                                    

Measured value 1 and 2 in parallel: 171.3Ω

           

What principles of electricity have you demonstrated with this? Explain:

In the series circuit the total resistance equals the sum of each resistor. For example

Rt = (R1 + R2). In this circuit if only one resistor fails the circuit would become open and electric charge would not be able to flow.

In the Parallel circuit the total resistance can be found using the following formula Rt = (R1XR2/R1+R2). The total resistance in a Parallel circuit must be smaller than the smallest resistor. The advantage of this circuit is that if one of the resistors fail that is the only resistor which is extinguished.