Going back in time, meters were rated in ohms per volt full scale sensitivity. This means that if a meter was rated at 20Kohms per volt and it had a 1 volt scale, it would represent a 20Kohm additional load on the circuit it was attached to. In some circuits the additional load could change the operation of the circuit, and/or the measurement. Analog meters usually had this rating. I guess very cheap ones today are still this way.
Modern meters generally have a sensitivity in excess of 11Megaohms/volt, so this is no longer a problem for simple measurements.
The purpose of a voltmeter is to indicate the potential difference between two points in a circuit.When a voltmeter is connected across a circuit, it shunts the circuit. If the voltmeter has a low resistance,it will draw a substantial amount of current. This action lowers the effective resistance of the circuit andchanges the voltage reading.
A voltmeter must have a very high resistance to measure voltage. A voltmeter is placed in parallel with the element that you are measuring. If the voltmeter has a low internal resistance, then all of the current will flow through the voltmeter instead of the element. You want all of the current to flow through the element, to get an accurate reading of the voltage. Conversely, an ampmeter must have zero resistance, because it is placed in series with the element.
Smoke. Since a voltmeter is in parallel with the load it is right across the source voltage. Putting the amp meter across the line with its low resistance it will act like a fuse, hence the smoke. Newer solid state testers are usually smarter that the operators. They have built in circuitry which sense the wrong settings you are using and shut the tester off with a "beep" to let you know that you are doing something wrong.
positive terminal
Red wire from a regular DC voltmeter should be connected to :
high noise level and low sensitivity
It depends on your definition of sensitivity. Sensitivity might mean how low a reading the voltmeter can accurately indicate, or it might mean how high the impedance the voltmeter presents to the circuit. An old Triplett 310 I have can resolve 50 mV +/- 3% at an impedance of 60 KOhms on a DC scale, which by today's standards is not very good, but by standards of 40 years ago was nearly state-of-the-art. A more modern digital meter I have, a Radio Shack DVM, can resolve 0.1 mV +/- 1% at an impedance of 11 MOhms, which is actually only middle-of-the-road today, but still very usable in many applications.
To minimize the loading effect on a voltmeter, use a voltmeter with a high input impedance. This will ensure that the voltmeter draws as little current as possible from the circuit being measured, reducing the impact on the voltage being measured. Additionally, connecting the voltmeter in parallel with the circuit, rather than in series, can also help minimize the loading effect.
Digital voltmeter has high input impedence.
The least count of a voltmeter is the smallest measurable change in voltage that the device can detect. It is determined by the resolution of the display and the sensitivity of the measuring components. It is important for accurate voltage measurement.
You mean fastest? Digital voltmeter gives reading in seconds.
One does NOT insert a voltmeter in a series cirtcuit...an ammeter can be inserted in series, though. A voltmeter is connected in parallel with the source voltage and low(ground) side.
S = 1/ Ifsd = 1/5mA = 200 Ohm / V
S = 1/ Ifsd = 1/5mA = 200 Ohm / V
S = 1/ Ifsd = 1/5mA = 200 Ohm / V
The purpose of a voltmeter is to indicate the potential difference between two points in a circuit.When a voltmeter is connected across a circuit, it shunts the circuit. If the voltmeter has a low resistance,it will draw a substantial amount of current. This action lowers the effective resistance of the circuit andchanges the voltage reading.
It is the speed at which you turn. For example, if your sensitivity is 1 (Low) you will turn slower than if you sensitivity is on 4 (High).