What must be done to a circuit before you can use an ohmmeter for testing?

What must be done to a circuit before you can use an  ohmmeter for testing?
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1 Answer

Answer :

It must be de-energized.
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Related questions

Before you connect a VOM in a circuit for an ohmmeter reading, in what condition must the circuit be?

Description : Before you connect a VOM in a circuit for an ohmmeter reading, in what condition must the circuit be?

Last Answer : De-energized

When you are testing the gain of an audio-frequency transistor with an ohmmeter, what is indicated by a 10-to-1 resistance ratio?

Description : When you are testing the gain of an audio-frequency transistor with an ohmmeter, what is indicated by a 10-to-1 resistance ratio?

Last Answer : Normal gain.

When testing an SCR with an ohmmeter, the SCR will conduct if what two elements are shorted together?

Description : When testing an SCR with an ohmmeter, the SCR will conduct if what two elements are shorted together?

Last Answer : Gate and anode.

To avoid damaging the components of a printed circuit board when testing it with a DC volt-ohmmeter, you should _______. A. ground the board B. avoid reversing the polarity of the leads C. isolate sensitive components with heat sinks D. all of the above

Description : To avoid damaging the components of a printed circuit board when testing it with a DC volt-ohmmeter, you should _______. A. ground the board B. avoid reversing the polarity of the leads C. isolate sensitive components with heat sinks D. all of the above

Last Answer : Answer: B

How is a series-type ohmmeter connected to the circuit being measured?

Description : How is a series-type ohmmeter connected to the circuit being measured?

Last Answer : The ohmmeter is connected in series with the resistance to be measured.

What are two transistor tests that can be done with an ohmmeter?

Description : What are two transistor tests that can be done with an ohmmeter?

Last Answer : Gain and junction resistance.

While testing a semi-conductor diode with an ohmmeter, both the forward and reverse readings are almost in the infinity range. This would indicate that the unit is _____________. A. good B. open C. grounded D. shorted

Description : While testing a semi-conductor diode with an ohmmeter, both the forward and reverse readings are almost in the infinity range. This would indicate that the unit is _____________. A. good B. open C. grounded D. shorted

Last Answer : Answer: B

When testing a capacitor with an analog type ohmmeter, a good capacitor will be indicated when _____________. A. there is no meter deflection B. the meter deflects to a low resistance value and remains there C. the meter deflects to a low resistance value and slowly increases towards infinity D. the meter deflects to a low resistance value and increases rapidly to a higher value, but stays fairly low

Description : When testing a capacitor with an analog type ohmmeter, a good capacitor will be indicated when _____________. A. there is no meter deflection B. the meter deflects to a low resistance value and ... deflects to a low resistance value and increases rapidly to a higher value, but stays fairly low

Last Answer : Answer: C

When you are using an ohmmeter to test a transistor for leakage, what is indicated by a low, but not shorted, reverse resistance reading?

Description : When you are using an ohmmeter to test a transistor for leakage, what is indicated by a low, but not shorted, reverse resistance reading?

Last Answer : A leaking transistor

When checking a diode with an ohmmeter, what is indicated by two high resistance measurements?

Description : When checking a diode with an ohmmeter, what is indicated by two high resistance measurements?

Last Answer : The diode is open or has a high-forward resistance.

When you are using an ohmmeter to test a transistor, what range settings should be avoided?

Description : When you are using an ohmmeter to test a transistor, what range settings should be avoided?

Last Answer : Any range setting that produces a current flow through the transistor that exceeds 1 milliamp (usually R x 1 range)

How could you check a 1/500-ampere fuse with an ohmmeter?

Description : How could you check a 1/500-ampere fuse with an ohmmeter?

Last Answer : Use a resistor in series with the fuse when you check it with the ohmmeter.

You have just checked a 1/500-ampere fuse with an ohmmeter and find it is open. Checking the replacement fuse shows the replacement fuse is open also. Why would the replacement fuse indicate open?

Description : You have just checked a 1/500-ampere fuse with an ohmmeter and find it is open. Checking the replacement fuse shows the replacement fuse is open also. Why would the replacement fuse indicate open?

Last Answer : The ohmmeter causes more than 1/500 ampere through the fuse when you check the fuse, thus it opens the fuse.

You have just checked a fuse with an ohmmeter and find that the fuse is shorted. What should you

Description : You have just checked a fuse with an ohmmeter and find that the fuse is shorted. What should you

Last Answer : Put it back in the circuit. A good fuse will have zero ohms of resistance.

What area of an ohmmeter scale should be used when measuring circuits?

Description : What area of an ohmmeter scale should be used when measuring circuits?

Last Answer : The middle of the scale.

What is used to provide the ohmmeter with several ranges?

Description : What is used to provide the ohmmeter with several ranges?

Last Answer : An ohmmeter has several internal range resistors and a switch or a series of jacks to select the proper range.

What other measurement can an ohmmeter make?

Description : What other measurement can an ohmmeter make?

Last Answer : Circuit continuity.

What electrical quantity is measured by an ohmmeter?

Description : What electrical quantity is measured by an ohmmeter?

Last Answer : Resistance.

The R x 100 resistance selection on an ohmmeter has what amount of resistance compared to the R x 10 selection?

Description : The R x 100 resistance selection on an ohmmeter has what amount of resistance compared to the R x 10 selection?

Last Answer : 1/10.

. A full-scale deflection on an ohmmeter scale indicates what resistance between the leads?

Description : . A full-scale deflection on an ohmmeter scale indicates what resistance between the leads?

Last Answer : Zero.

The R x 100 resistance selection on an ohmmeter has what amount of resistance compared to the R x 10 selection?

Description : The R x 100 resistance selection on an ohmmeter has what amount of resistance compared to the R x 10 selection?

Last Answer : 1/10.

A full-scale deflection on an ohmmeter scale indicates what resistance between the leads?

Description : A full-scale deflection on an ohmmeter scale indicates what resistance between the leads?

Last Answer : Zero.

When you are testing individual components in a circuit, what may cause a defective component to appear good?

Description : When you are testing individual components in a circuit, what may cause a defective component to appear good?

Last Answer : A parallel resistor or diode of similar value.

To conduct an in-circuit test of a transistor, you should use a/an ____________. A. voltmeter or transistor tester B. impedance meter C. ohmmeter or transistor tester D. wattmeter

Description : To conduct an in-circuit test of a transistor, you should use a/an ____________. A. voltmeter or transistor tester B. impedance meter C. ohmmeter or transistor tester D. wattmeter

Last Answer : Answer: A

When troubleshooting a console circuit card suspected of being faulty, first check operating voltages, clean the card and then _________________. A. make sure wired connections and push-on connectors are tight B. test each resistor and capacitor on the card with an ohmmeter C. check the continuity of all printed circuit traces with an ohmmeter D. measure the gain of each transistor or integrated circuit

Description : When troubleshooting a console circuit card suspected of being faulty, first check operating voltages, clean the card and then _________________. A. make sure wired connections and push-on connectors ... circuit traces with an ohmmeter D. measure the gain of each transistor or integrated circuit

Last Answer : Answer: A

Which of the meters listed should only be used after a circuit has been electrically disconnected? A. Wattmeter B. Frequency meter C. Ammeter D. Ohmmeter

Description : Which of the meters listed should only be used after a circuit has been electrically disconnected? A. Wattmeter B. Frequency meter C. Ammeter D. Ohmmeter

Last Answer : Answer: D

An ohmmeter can be used to measure ____________. A. current flow in a circuit B. voltage between two points in a circuit C. circuit continuity D. power

Description : An ohmmeter can be used to measure ____________. A. current flow in a circuit B. voltage between two points in a circuit C. circuit continuity D. power

Last Answer : Answer: C

With both ends of a three conductor cable disconnected and arranged without the conductors touching each other, an ohmmeter reading of 'zero' ohms between the ends of one conductor would indicate _____________. A. continuity B. a partial ground C. the resistance is infinite D. a short circuit

Description : With both ends of a three conductor cable disconnected and arranged without the conductors touching each other, an ohmmeter reading of 'zero' ohms between the ends of one conductor would indicate _____________. A. continuity B. a partial ground C. the resistance is infinite D. a short circuit

Last Answer : Answer: A

When troubleshooting an electronic circuit, a cold solder joint can be located with the aid of an ohmmeter. Once the problem has been located, you should _________________. A. reheat the circuit in an oven to an even temperature and recheck with an ohmmeter B. reheat the connection with a match and recheck with an ohmmeter C. reheat connection with a soldering tool and recheck with an ohmmeter D. do nothing as this is the normal condition

Description : When troubleshooting an electronic circuit, a cold solder joint can be located with the aid of an ohmmeter. Once the problem has been located, you should _________________. A. reheat the circuit in an ... a soldering tool and recheck with an ohmmeter D. do nothing as this is the normal condition

Last Answer : Answer: C

In order to check the performance of a transistor removed from its circuit, the instrument to be used should be a/an ____________. A. voltmeter or transistor tester B. impedance meter C. ohmmeter or transistor tester D. sensitive potentiometer

Description : In order to check the performance of a transistor removed from its circuit, the instrument to be used should be a/an ____________. A. voltmeter or transistor tester B. impedance meter C. ohmmeter or transistor tester D. sensitive potentiometer

Last Answer : Answer: C

Before using a volt-ohmmeter to measure resistance readings, you should _____________. A. replace all batteries B. test the insulation resistance of the leads C. make sure the test leads do not touch D. hold the leads together and 'zero' the meter

Description : Before using a volt-ohmmeter to measure resistance readings, you should _____________. A. replace all batteries B. test the insulation resistance of the leads C. make sure the test leads do not touch D. hold the leads together and 'zero' the meter

Last Answer : Answer: D

Before measuring an unknown resistance with an ohmmeter, you should _____________. A. adjust the meter's pointers to mid-scale B. change the meter's batteries C. center the meter's pointer at infinity D. short the test leads and calibrate the meter

Description : Before measuring an unknown resistance with an ohmmeter, you should _____________. A. adjust the meter's pointers to mid-scale B. change the meter's batteries C. center the meter's pointer at infinity D. short the test leads and calibrate the meter

Last Answer : Answer: D

Before measuring an unknown resistance with an ohmmeter, you should _____________. A. adjust the meter's pointer to mid-scale B. short the test leads and calibrate the meter reading to 'zero' C. change the meter's batteries D. center the meter's pointer at infinity

Description : Before measuring an unknown resistance with an ohmmeter, you should _____________. A. adjust the meter's pointer to mid-scale B. short the test leads and calibrate the meter reading to 'zero' C. change the meter's batteries D. center the meter's pointer at infinity

Last Answer : Answer: B

Which of the following actions must be carried out before a voltage tester can be used to test the three line fuses to a three-phase motor? A. The fuses must be removed from the circuit. B. The starter must be placed in the STOP position to stop the motor. C. The three line connections in the motor terminal box must be disconnected and tagged. D. Nothing need be done as long as the motor is running under a light load.

Description : Which of the following actions must be carried out before a voltage tester can be used to test the three line fuses to a three-phase motor? A. The fuses must be removed from the circuit. B. The ... disconnected and tagged. D. Nothing need be done as long as the motor is running under a light load.

Last Answer : Answer: B

You are using a mechanical voltage tester to check the fuses in a three-phase circuit supplying an electric motor. For which of the following reasons must the motor be stopped during the test? A. Testing an energized circuit presents a hazard to the testing personnel. B. A faulty fuse could go undetected with the motor energized. C. Reversed polarity of the circuit would be indicated by the voltage tester with the circuit energized. D. All of the above.

Description : You are using a mechanical voltage tester to check the fuses in a three-phase circuit supplying an electric motor. For which of the following reasons must the motor be stopped during the test? A. ... circuit would be indicated by the voltage tester with the circuit energized. D. All of the above.

Last Answer : Answer: B

In testing a three-phase delta winding for an open circuit using a megohmmeter, you must ______________. A. test each phase with all connections intact B. measure the voltage across the open connections while testing C. test the windings as parallel groups to avoid short circuiting D. open the delta-connections to avoid shunting the phase being tested

Description : In testing a three-phase delta winding for an open circuit using a megohmmeter, you must ______________. A. test each phase with all connections intact B. measure the voltage across the open ... groups to avoid short circuiting D. open the delta-connections to avoid shunting the phase being tested

Last Answer : Answer: D

What must be used to test an activated circuit?

Description : What must be used to test an activated circuit?

Last Answer : Approved meters or other indicating devices

What conditions must be met in order to balance a bridge circuit?

Description : What conditions must be met in order to balance a bridge circuit?

Last Answer : A bridge circuit is balanced when the opposite legs of the comparing and measuring circuits exhibit the same voltage drop.

A circuit is to be designed in which a capacitor must charge to 40 percent of the maximum charging voltage in 200 microseconds. The resistor to be used has a resistance of 40,000 ohms. What size capacitor must be used?

Description : A circuit is to be designed in which a capacitor must charge to 40 percent of the maximum charging voltage in 200 microseconds. The resistor to be used has a resistance of 40,000 ohms. What size capacitor must be used?

Last Answer : 0.1 microfarads 40% from the graph = 0.5

When using a megohmmeter to determine which shunt field coil is grounded in a DC machine, you must ____________. A. insulate the field frame from the ship's hull B. disconnect each shunt field coil before testing C. use a motor driven high capacity megohmmeter D. remove all main line lead connections before testing

Description : When using a megohmmeter to determine which shunt field coil is grounded in a DC machine, you must ____________. A. insulate the field frame from the ship's hull B. disconnect each shunt ... C. use a motor driven high capacity megohmmeter D. remove all main line lead connections before testing

Last Answer : Answer: B

What safety precaution must be taken before replacing a transistor?

Description : What safety precaution must be taken before replacing a transistor?

Last Answer : The power must be removed from the circuit.

Before a diode will conduct, the cathode must be what polarity relative

Description : Before a diode will conduct, the cathode must be what polarity relative

Last Answer : Negative.

When troubleshooting electronic equipment, the FIRST step to be taken before testing the circuit voltage is to _________. A. set the meter to the lowest range B. check the voltage supply from the power source C. remove the suspected component D. check the current flow through the circuit

Description : When troubleshooting electronic equipment, the FIRST step to be taken before testing the circuit voltage is to _________. A. set the meter to the lowest range B. check the voltage supply from the power source C. remove the suspected component D. check the current flow through the circuit

Last Answer : Answer: B

What steps are to be taken before beginning work on a circuit breaker

Description : What steps are to be taken before beginning work on a circuit breaker

Last Answer : Check the applicable technical manual, obtain the approval of the electrical or engineering officer (for shipboard circuit breakers), remove power from the circuit breaker, and tag the switch that supplies power to the circuit breaker.