How to Read a Volt Amp Meter
Contributors: 
Measuring Voltage
To start, let's mensurate voltage on a AA battery: Plug the black probe into COM and the ruby-red probe into mAVΩ. Set the multimeter to "2V" in the DC (direct current) range. Almost all portable electronics apply straight current), non alternate current. Connect the black probe to the battery's footing or '-' and the ruby-red probe to power or '+'. Clasp the probes with a footling pressure level against the positive and negative terminals of the AA battery. If you lot've got a fresh battery, you should see around 1.5V on the display (this battery is brand new, and then its voltage is slightly higher than 1.5V).
If y'all're measuring DC voltage (such every bit a battery or a sensor hooked up to an Arduino) y'all want to gear up the knob where the V has a directly line. AC voltage (like what comes out of the wall) can be dangerous, so nosotros rarely need to use the AC voltage setting (the 5 with a wavy line adjacent to information technology). If you're messing with Ac, we recommend you go a non-contact tester rather than utilise a digital multimeter.
Use the Five with a straight line to measure out DC Voltage
Apply the V with a wavy line to measure Air conditioning Voltage
What happens if you switch the red and black probes? The reading on the multimeter is simply negative. Null bad happens! The multimeter measures voltage in relation to the common probe. How much voltage is there on the '+' of the battery compared to mutual or the negative pin? one.5V. If nosotros switch the probes, we ascertain '+' equally the mutual or zero indicate. How much voltage is at that place on the '-' of the bombardment compared to our new zero? -1.5V!
Now let'south construct a simple circuit to demonstrate how to mensurate voltage in a real globe scenario. The circuit is but a 1kΩ and a Blue super bright LED powered with a SparkFun Breadboard Power Supply Stick. To brainstorm, permit's brand certain the circuit you are working on is powered up correctly. If your project should be at 5V but is less than four.5V or greater than 5.5V, this would quickly give you an indication that something is wrong and you may need to cheque your power connections or the wiring of your circuit.
Measuring the voltage coming off of a Power Supply Stick.
Set the knob to "20V" in the DC range (the DC Voltage range has a V with a directly line adjacent to it). Multimeters are generally not autoranging. You lot have to set the multimeter to a range that information technology can measure. For example, 2V measures voltages upwardly to two volts, and 20V measures voltages upwards to 20 volts. And then if you've measuring a 12V battery, use the 20V setting. 5V organization? Use the 20V setting. If you lot prepare information technology incorrectly, y'all will probably come across the meter screen alter and and so read '1'.
With some strength (imagine poking a fork into a piece of cooked meat), push button the probes onto ii exposed pieces of metallic. 1 probe should contact a GND connection. One probe to the VCC or 5V connection.
We tin examination different parts of the circuit too. This do is called nodal analysis, and it is a basic building block in circuit analysis. Past measuring the voltage across the circuit nosotros tin see how much voltage each component requires. Let's measure the whole circuit start. Measuring from where the voltage is going in to the resistor and then where ground is on the LED, we should see the full voltage of the circuit, expected to be effectually 5V.
Nosotros can and so see how much voltage the LED is using. This is what is referred to as the voltage drop across the LED. If that doesn't make sense now, fright not. It will every bit y'all explore the world of electronics more. The important thing to take abroad is that different parts of a circuit can be measured to clarify the circuit as a whole.
This LED is using two.66V of the available 5V supply to illuminate. This is lower than the forward voltage stated in the datasheet on business relationship of the circuit only having small corporeality of electric current running though it, but more on that in a chip.
Overload
What happens if you select a voltage setting that is likewise low for the voltage you're trying to measure? Cipher bad. The meter will just brandish a ane. This is the meter trying to tell you that information technology is overloaded or out-of-range. Any you're trying to read is also much for that particular setting. Try changing the multimeter knob to a the next highest setting.
Reading the 5V beyond this circuit is too much for the 2V setting on the multimeter.
Selection Knob
Why does the meter knob read 20V and not 10V? If you're looking to measure a voltage less than 20V, yous turn to the 20V setting. This will permit you to read from two.00 to 19.99.
The first digit on many multimeters is only able to display a 'ane' and so the ranges are limited to 19.99 instead of 99.99. Hence the 20V max range instead of 99V max range.
Alarm! In general, stick to DC circuits (the settings on the multimeter with directly lines, not curvy lines). Most multimeters can measure AC (alternate current) systems, simply Air conditioning circuits can be dangerous. A wall outlet with AC or 'main voltage' is the stuff that tin can zap you lot pretty practiced. VERY advisedly respect AC. If you demand to check to see if an outlet is 'on' and so use a AC tester. Actually the only times nosotros've needed to measure Air-conditioning are when we've got an outlet that is acting funny (is it really at 110V?), or if we're trying to command a heater (such every bit a hot plate). Go irksome and double bank check everything before you test an AC excursion.
Source: https://learn.sparkfun.com/tutorials/how-to-use-a-multimeter/measuring-voltage
0 Response to "How to Read a Volt Amp Meter"
Post a Comment