Chapter 6 Electromechan e r m m c a a ni cal a S Sy s st ems e s 14 43 Copyright Goodheart-Willcox Co., Inc. Copyright Goodheart-Willcox Co., Inc. current value of each range is the maximum current that may be measured on that range. When making current measurements, adjust the function-select switch or push button to the highest range of current. The red test lead should be put into the mA jack. The black test lead should be put into the COM jack. Current values are usually indicated in milliampere units on the digital scale of the meter. To measure current with an autoranging multimeter, the range values do not need to be changed for larger or smaller values. The negative (black) lead is inserted in the COM jack and the positive (red) lead is placed in the mA jack of f the meter. The function select switch is adjusted to the mA (milliamperes) or μA (microamperes) setting, either dc or ac. Current values are indicated in milliam- peres or microamperes, corresponding with the setting on the digital scale of the meter. The multimeters discussed are representative of the types of digital meters used. The most common type has separate ranges that need to be set for making resistance, voltage, and current measurements. The autoranging meter needs only to be set for the desired function for measuring voltage, current, or resistance. Analysis Obtain a meter to use for completing your lab activities. Study the meter and answer each of the following questions. Indicate N/A (not applicable) if the item does not apply to your meter. Explain at the end of the item. 1. What company manufactured the meter? 2. What is the model number of the meter? 3. The meter will measure up to what A of dc? 4. True or False? Ohms-adjust control is used each time the resistance range is changed. 5. To measure dc current greater than1 A, the range switch is placed in what position? 6. For measuring current in a circuit, the meter should be connected how (series or parallel)? 7. For measuring voltage, the meter should be connected how (series or parallel)? 8. To measure 18 mA of current, the range switch should be placed in what position? 9. To measure 10 μA of current, the range switch should be placed in what range? 10. To measure resistance, the red test lead must be placed in the jack with what marking? The black test lead must be placed in the jack with what marking? 11. True or False? Polarity must be observed when measuring ac voltage. 12. True or False? Polarity is not important when measuring resistance. 13. Up to how many volts dc can be measured with the meter? 14. For measuring a resistor valued at 10 Ω, what range should be used? 15. True or False? Polarity should be observed when measuring dc voltage. 16. True or False? It is correct to measure the resistance of a circuit with voltage applied. 17. True or False? When measuring an unknown value of voltage, one should start at the highest range and work down to the lowest value without exceeding the measured value. 18. True or False? Meters should always be handled with care and safety.