Obtain 15 resistors Estimate their value using the Resistor

Obtain 15 resistors. Estimate their value using the Resistor Color Code Chart and record it into Table 1 along with the minimum and maximum values. Now use the DMM to measure the values of the resistors and record them in the proper cell. Do all the DMM measured values fall within the minimum and maximum values? If Not, why? Why do you think the DMM values and the nominal values do not agree with each other? Why do you think it\'s incorrect to measure the resistance after plugging the resistor into the circuit?

Solution

1. DMM values may or may not fall within the max & min values. The value of the resistance depends on the temperature also. The value of the resistance on it specified will be at the room temperature. If the temperature increases the value of resistance also increases. And each resistor can have different tolerance band & for only some resistances the nominal value meets the actual value

2. The dmm values and the nominal values may not agree with each other, as there may occur error in the measurement unit. Each mesurement can have two types of errors viz., random error and systematic error. All these should be taken into consideration while measuring resistance.

3. While measuring resistance with dmm the resistors should be taken out of the circuit. As the dmm injects a small current into the resistor for which the resistance is being measured, measuring the resistance using dmm with resistor in the circuit can cause some current to flow through the other part of the circuit thus giving an incorrect value of the resistance.