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How much resistance will an ohmmeter indicate across a good capacitor?
Wiki User
∙ 12y ago
Wiki User
∙ 12y agoThink of a capacitor as two metal plates that are parallel to each other with a gap in between the plates. A charge accumulates on one plate when a DC voltage is across the plates. Therefore, no DC current flows across the air gap. The capacitor holds the charge until there is a path to ground and the capacitor discharges.
When there is an AC voltage across the plates of the capacitor the charge is continually going up and down.
If you were to try and measure resistance with an ohm meter across a capacitor it would register as an open circuit, because the meter is using DC.
Hence, it doesn't make sense to talk about the resistance of a capacitor, only its capacitance which is a measure of the amount of charge it can hold.
Wiki User
∙ 15y agoCompletely discharged, a capacitor does not restrict current flow. So its resistance is effectively zero.
Wiki User
∙ 12y ago[ R x C ] = [ 1/Time ]
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How much electrical resistance would you expect an ohmmeter to indicate if it were connected across the combination of these two series connected resistors of 3.3 kilowatt ohms and 3.3 kilowatt ohms?
It would be the sum of the two resistances, as they are connected in series.
What is different of common emitter amplified with capacitor and without capacitor?
It depends on where the capacitor is located. If it is across the emitter resistor, then the gain of the CE amplifier will be higher at higher frequencies.Remember that gain in the CE amplifier is collector resistance divided by emitter resistance, or hFe, whichever is lower. Placing a capacitor across the emitter resistor will serve to make the effective resistance smaller at higher frequencies, resulting in increased gain, up to the limit of hFe.If this is not the intended location of the capacitor, then please restate the question and provide the capacitor location.
Why can't you use a multitester as an ohmmeter if it has no battery?
The battery is used by the meter to apply a voltage across the resistance being measured and determine the current which determines the resistance. If there is no battery it can't supply the voltage and can't measure current, so no reading.
How is an ohmmeter connected to a circuit?
ANY METER needs some kind of current flow to operate. Internal in the meter there are batteries that provide current that when passed trough a resistor will develop voltage as a function of the current. the meter will read this current and display the resistor size to cause this current to flow.
What is leakage resistance in RC circuit?
Leakage resistance in any circuit is resistance less than infinity where it is not expected, such as across an insulator. In the ideal sense, all circuits have leakage resistance because no insulator is perfect, but we usually ignore this except in special situations because it does not normally matter in real applications. In an RC circuit, leakage resistance would most typically be across the capacitor.
How much electrical resistance would you expect an ohmmeter to indicate if it were connected across the combination of these two series connected resistors of 3.3 kilowatt ohms and 3.3 kilowatt ohms?
It would be the sum of the two resistances, as they are connected in series.
What is different of common emitter amplified with capacitor and without capacitor?
It depends on where the capacitor is located. If it is across the emitter resistor, then the gain of the CE amplifier will be higher at higher frequencies.Remember that gain in the CE amplifier is collector resistance divided by emitter resistance, or hFe, whichever is lower. Placing a capacitor across the emitter resistor will serve to make the effective resistance smaller at higher frequencies, resulting in increased gain, up to the limit of hFe.If this is not the intended location of the capacitor, then please restate the question and provide the capacitor location.
What is use of capacitor Ce across emitter resistance?
It can be used as a feedback and to ground unwanted signals and frequencies
Why bypass capacitor is used in common emitter ampifier circuit?
If a bypass capacitor is used the voltage drop across emitter resistance is reduced which in turn increases the gain.....
What is capacitor reactant?
Capacitive reactance is an opposition to changes in voltage across an element. This resistance is usually caused by a magnetic field.
Why can't you use a multitester as an ohmmeter if it has no battery?
The battery is used by the meter to apply a voltage across the resistance being measured and determine the current which determines the resistance. If there is no battery it can't supply the voltage and can't measure current, so no reading.
How is an ohmmeter connected to a circuit?
ANY METER needs some kind of current flow to operate. Internal in the meter there are batteries that provide current that when passed trough a resistor will develop voltage as a function of the current. the meter will read this current and display the resistor size to cause this current to flow.
Why must power be turned off when measuring the resistance of a circuit?
If an external Voltage is applied to a multimeter while the multimeter`s function switch is in the Ohm meter position then the Ohmmeter is apt to be destroyed or disabled. Therefore the simplest answer is that the power must be turned off in order to avoid damage to the Ohm meter and possibly to yourself caused by Voltages present in the circuit while the power is own. Another reason of course is because a valid Ohm reading can not be obtained while Voltages are present across the resistance that is being measured because the Ohmmeter itself applies a Voltage across the resistance and then a sampling of the current through the unknown resistance is used by the Ohmmeter`s circuitry to cause a calibrated deflection of the Ohmmeter and thus display on the meter`s dial the Ohmic value of the unknown resistance. For the same reasons as above it is also a good practice to discharge all the capacitors in the circuit after the power is turned off and before any in circuit resistance measurements are made.
What is leakage resistance in RC circuit?
Leakage resistance in any circuit is resistance less than infinity where it is not expected, such as across an insulator. In the ideal sense, all circuits have leakage resistance because no insulator is perfect, but we usually ignore this except in special situations because it does not normally matter in real applications. In an RC circuit, leakage resistance would most typically be across the capacitor.
How do you check a capacitor to see if it is good or bad?
There are many ways. FIRST: short the terminals to ensure it is not charged. Many of the digital meters today also have a capacitance check setting, simply use that setting. It not only checks for faults, but also will give you a reading of the capacitance value itself. For most non-electrolytic capacitors a quick check (definately bad vs. maybe good) can be done with an analog VOM. Use the highest resistance scale to measure across the terminals. When first connected there should be a short needle jump that slowly drops back to infinity. Reverse the leads and do it again, should have the same effect. Any resistance highter than infinity indicates a shorted capacitor. Lack of needle jump may indicate an open capacitor (or one of very little capacitance). Electrolytics can also be checked with a VOM, but polarity must be observed, and the drop back to infinity may take a very long time. Alternatively, for electrolytics and larger capacitors is to charge them with a low voltage source (e.g. 9V battery) and measure with multimeter to see if they hold the charge.
What two facctors determine the capacitive reactance of a capacitor?
The reactance of a capacitor is a function of -- the capacitance of the capacitor -- the frequency of the voltage across the capacitor
Why should an ohmmeter never be used on an energized circuit?
Because an ohmmeter works by putting a potential difference (voltage) across a load and measuring the resulting current (the current will be inversely proportionate to the resistance). In a live circuit there is already current flowing through the load so (at best) the reading will be inaccurate, at worst the meter will be damaged.
