Multimeters - Measuring Current - Electronics Basics 16

hello once again onde welcome to the 16th episode of simply electronics basics today we're going to have a look at how to measure current using a multimeter make sure you check out the previous video where we learned how to measure resistance and continuity now to get started I have a simple LED circuit setup on a breadboard and I want to measure the current that is flowing through the LED the circuit simply consists of a 5 volt USB power supply with a 100 ohm series resistor now we could calculate the current that flows through this led by calculating the current that flows through the resistor because this is a series circuit the current flowing through the resistor is the same as the current flowing through the LED so to calculate current the equation is the current is equal to the voltage divided by the resistance this resistor is a hundred ohms and the voltage is 5 volts this gives us a result of 20 milliamps or 0.02 amps now if I want to verify that with a multimeter I can do so with this multimeter you can see there are many different modes for measuring different values so I have the black probe connected to the comm port where it should always be connected and I have the red probe connected in the port that allows me to measure voltage resistance and low current now I calculated very briefly that there should be 20 milliamps across this led I can actually select the 20 milliamp range on this multimeter but what if I am slightly over 20 milliamps let's say I'm getting twenty five milliamps across this led to be safe I'm going to select the two hundred milliamps range if I want a more accurate measurement later and the result is under 20 milliamps I can turn it to the 20 milliamp range and get a more accurate answer now if you saw in the last video when you're measuring resistance you put the probes across the resistor however it is very different when you're measuring current in a circuit when you want to measure current going through a component you actually need to put the multi in series with the circuit so instead of putting the multimeter in parallel across a circuit it needs to be in series so you can see I have a positive power cable coming from the power supply to the led so if I want to measure the current going through this led I need to connect the multimeter in series I'm going to disconnect the wire from the led and I'm going to insert another wire onto the positive pin of the LED so just pretend this is all one cable by adding this extra wire all I have now done is created a break in the middle of that wire this will now enable me to connect the multimeter in series with this circuit and you can see I've connected the positive and negative probe between these two wires and therefore completed the circuit so as you can see this multimeter is now connected in series with the LED circuit the LED is glowing and I have a measurement on the screen it is measuring twenty point three milliamps pretty much exactly what I calculated with this particular multimeter and most other multimeters if I want to measure over 200 milliamps I have to do two things firstly I need to select the high amp range on a multimeter with this multimeter I can measure up to 10 amps DC current it is very important when I want to measure a high amperage on a multimeter I use the dedicated port for measuring that kind of current so I've taken my red probe away from the volt resistance a milli ampere range and now I need to connect it to the 10 amps DC port it is important that you do this if I try to send 10 amps through this port I may destroy the multimeter but most likely blow a fuse in this case I just want to measure the short-circuit current from my power supply I know it should be approximately 1 amp so I've set my multimeter to the 10 amp range all I now need to do is connect the probes in series with the power supply I actually get a measurement here of 0.45 amps now I thought that this power supply was delivering around 1 amp ok so thank you for watching make sure you subscribe to keep up to date with the latest videos from simply electronics give this video a thumbs up if you enjoyed and leave your comments below

Channel: Simply Electronics

Views: 34,571

Rating: 4.9695044 out of 5

Keywords: electronics, basics, current, electric, electron, flow, tutorial, how, to, energy, hobby, multimeter, power, circuit, volts, amps, watts, solder, iron, soldering, simple, simply, making, bigclive, big, clive, bigclivedotcom, diy, hack, roman, ursu, arduino, how to measure current, multimeter current, measure amps with multimeter, how to use a multimeter, multimeter to measure current, measure amps, multimeter in series

Id: 7XYdMZPuM5c

Length: 4min 46sec (286 seconds)

Published: Fri Aug 12 2016