An ohmmeter scale reaches half scale deflection when at 1500 ohm calculate the variable resistance needed to make the pointer reach the maximum reading
To calculate the variable resistance needed to make the pointer reach the maximum reading on an ohmmeter, we need to determine the full scale deflection value of the ohmmeter.
We are given that the half scale deflection of the ohmmeter occurs at 1500 ohms. This means that when the resistance being measured is 1500 ohms, the pointer is at half of its maximum deflection.
To find the full scale deflection value, we can assume that the ohmmeter has a linear response. This means that the deflection of the pointer is directly proportional to the resistance being measured. Therefore, if the half scale deflection happens at 1500 ohms, then the full scale deflection would occur at twice that value or 3000 ohms.
Now, to calculate the variable resistance needed to make the pointer reach the maximum reading, we need to find the difference between the full scale deflection value and the resistance being measured. In this case, the difference is 3000 ohms - 1500 ohms, which equals 1500 ohms.
Therefore, the variable resistance needed to make the pointer reach the maximum reading is 1500 ohms. This is because when the resistance being measured is 0 ohms (short circuit), the total resistance in the circuit would be 1500 ohms, resulting in the maximum reading on the ohmmeter.