DVOM Basics (Digital Volt Ohm Meter)

Summary

In this tech video, viewers are introduced to the fundamentals of car electrical systems using a digital volt-ohmmeter. The tutorial covers the three key terms: voltage (pressure), current (amperage), and resistance (ohms). Demonstrations include measuring voltage across a battery and a headlight circuit, testing resistance with a light bulb, and checking current flow in a light circuit. The video aims to make viewers proficient in using a DVOM for diagnosing car electrical issues.

Takeaways

• 🔌 To work on a car, understanding the basics of electricity is crucial, including voltage, current (amperage), and resistance (ohms).
• 💡 Voltage is like water pressure; it's the electro-motive force that a charged battery provides, typically around 12.6 volts in a car.
• 💧 Current, or amperage, represents the flow of electricity doing work, similar to water flowing through a pipe.
• ⚙️ Resistance (ohms) is the opposition to the flow of current, like a water wheel or a light bulb that does work when electricity passes through it.
• 🛠️ A digital volt-ohmmeter (DVOM) is a handy tool for measuring these three electrical properties in a vehicle's electrical system.
• 🔋 To measure voltage, you can connect the DVOM across the battery or within a circuit, such as from the battery to a headlight.
• 🔍 To check resistance, use the ohms setting on the DVOM and connect it across a component, like a light bulb, to measure its resistance value.
• 🔌 When measuring amperage, it's important to shunt the meter to protect it from high currents, which involves opening the circuit and connecting the meter in series.
• 🔦 The DVOM can be used to diagnose electrical issues in a car, such as finding the cause of a malfunctioning fuel pump or headlight.
• 👨‍🏫 The video emphasizes the importance of hands-on practice with a DVOM to become proficient in automotive electrical troubleshooting.
• 📢 The video also encourages viewers to follow the channel on social media platforms like Twitter and Facebook for more content.

Q & A

What are the three basic terms of electricity discussed in the video?

The three basic terms of electricity discussed in the video are voltage, current (also known as amperage), and resistance (measured in ohms).

How is voltage compared to water pressure in the video?

Voltage is compared to water pressure by illustrating that, like water, it is a form of pressure or force. The battery is described as a pressure maker, and the voltage is represented by the pressure in the water jug.

What is the typical voltage of a car battery when fully charged?

The typical voltage of a car battery when fully charged is about twelve point six volts.

What does the term 'amperage' refer to in the context of the video?

In the video, 'amperage' refers to the flow of electric current, which is the amount of electric charge passing through a conductor per unit of time.

How is resistance demonstrated in the video using a water wheel analogy?

Resistance is demonstrated using a water wheel analogy where the water wheel represents a device that does work against the flow of electricity, similar to how a fuel pump or wiper motor would in a car.

What is the purpose of using a digital volt ohmmeter (DVOM) in car repair?

A digital volt ohmmeter (DVOM) is used in car repair to measure voltage, current, and resistance, which helps diagnose electrical issues and ensures the proper functioning of the vehicle's electrical system.

How does the video explain the process of measuring voltage with a DVOM?

The video explains that to measure voltage with a DVOM, one can either connect it across the battery terminals or connect it across a specific circuit, such as a headlight, to check the voltage at that point.

What is the significance of measuring ohms of resistance in car electrical systems?

Measuring ohms of resistance is significant because it helps identify faulty components that may have increased resistance, which can prevent the proper flow of electricity and cause the device not to function.

Why is it important to shunt the meter when measuring amperage in the video?

It is important to shunt the meter when measuring amperage to protect the meter from potential damage. Shunting redirects some of the current away from the meter to prevent overloading it, especially since the meter is fused.

How does the video demonstrate measuring amperage with a DVOM?

The video demonstrates measuring amperage by first shunting the meter, then disconnecting the light bulb to open the circuit, and finally connecting the meter across the open circuit to measure the current flowing through the light bulb.

What is the final advice given in the video regarding using a DVOM for car electrical troubleshooting?

The final advice given in the video is to become proficient with using a DVOM to diagnose and fix electrical issues in cars, and to follow the channel on social media for more information.

Outlines

00:00

🔌 Understanding Car Electrical Systems

This paragraph introduces the basics of car electrical systems using the analogy of water pressure to explain voltage. It covers three key terms: voltage, current (amperage), and resistance (ohms). Voltage is likened to pressure, with the car battery acting as a pressure maker. The car's voltage is around 12.6 volts. Current is discussed as the flow of electricity, which does work in the form of resistance. An example is given where a wheel could be a fuel pump or a wiper motor, and resistance is the work done by the current. The paragraph concludes by introducing a digital volt-ohmmeter (DVOM) and explaining how to use it to measure voltage, resistance, and current in a car's electrical system.

Keywords

💡Digital Multimeter

A digital multimeter is an electronic measuring instrument that combines several measurement functions in one unit, including voltage, current, and resistance. In the video, it's used to diagnose electrical issues in a car. The script mentions using it to measure DC voltage, resistance (ohms), and current (amps), which are fundamental for understanding and troubleshooting car electrical systems.

💡Voltage

Voltage is the electric potential difference between two points. It's likened to water pressure in the script. The video explains that a car battery has a voltage of about 12.6 volts. Voltage is measured using the digital multimeter to ensure that the battery and other electrical components are providing the correct 'pressure' for the car's electrical system to function properly.

💡Current (Amperage)

Current, measured in amperes (amps), is the flow of electric charge. The script uses the analogy of water flowing through a pipe to explain current. In the context of the video, current is measured to ensure that electrical devices like light bulbs receive the necessary flow of electricity to operate, with the digital multimeter set to measure amps.

💡Ohms (Resistance)

Resistance is a measure of the opposition to the flow of electric current in a circuit. The script mentions using the digital multimeter to measure resistance, symbolized by the Greek letter Omega (Ω). Resistance is an important factor in determining how much current will flow through a circuit, and the video uses the example of a light bulb to illustrate how resistance is measured.

💡Electro-Motive Force (EMF)

Electro-motive force is the energy provided by a power source to drive an electric current through a circuit. In the script, the battery is described as a pressure maker, which is a layman's term for EMF. The video emphasizes that a charged battery has a certain voltage, which is the EMF that drives the current in the car's electrical system.

💡AC Voltage

AC voltage refers to the alternating current voltage, which oscillates periodically. The script briefly mentions AC voltage in the context of measuring wheel speed sensors or pickups in the distributor. It is one of the functions on the digital multimeter, but most car electrical systems operate on DC voltage, which is the focus of the video.

💡DC Voltage

DC voltage is the unidirectional flow of electric charge, as opposed to the alternating flow in AC systems. The video primarily focuses on DC voltage, which is the standard for most car electrical systems. The digital multimeter is used to measure DC voltage across the car's battery and other components to ensure they are functioning within the expected parameters.

💡Shunt

Shunt, in the context of the video, refers to a technique used when measuring current with a digital multimeter. The script explains that to measure current, the meter needs to be 'shunted' to protect it from high current flows. This involves opening the circuit and connecting the multimeter in series to measure the current without damaging the meter.

💡Circuit

A circuit is a closed loop through which electric current flows. The script discusses measuring voltage across a circuit, such as from the battery to a headlight, to check if the circuit is providing the necessary voltage for the light to function. Understanding circuits is crucial for diagnosing and fixing electrical issues in cars.

💡Electrical Gremlins

Electrical gremlins is a colloquial term for mysterious or hard-to-find electrical problems. The script uses this term to describe the types of issues that one might encounter when working on a car's electrical system. The video aims to help viewers identify and fix these gremlins using the digital multimeter and understanding of electrical principles.

Highlights

Introduction to using a digital volt ohmmeter for car repair

Explanation of the three basic terms of electricity: voltage, current, and resistance

Voltage described as pressure, with the car battery as a pressure maker

Demonstration of voltage with a water analogy

Current (amperage) explained as the flow of electricity doing work

Resistance (ohms) described as the opposition to the flow of electricity

Practical demonstration of measuring voltage across a car battery

Explanation of measuring voltage in a car's electrical circuit

Tutorial on how to use the ohms setting on a digital volt ohmmeter

Practical demonstration of measuring resistance with a light bulb

Introduction to measuring amperage (current flow) with the digital volt ohmmeter

Importance of shunting the meter to protect it when measuring amperage

Practical demonstration of measuring amperage in a car's electrical circuit

Advice on using the digital volt ohmmeter to diagnose electrical issues in cars

Encouragement to follow the channel on social media for more content

Transcripts

to work on a car today you're gonna need

one of these a digital vote ohmmeter

you're also gonna have to know the

basics of electricity today on tech

videos we're gonna take you through both

[Music]

three terms I like to talk about voltage

current which is amperage and ohms of

resistance let's start out with voltage

now like water voltage is pressure

electro-motive force our battery is a

pressure maker when you charge it it has

voltage our car has about twelve point

six volts you can see here the more I

put in the more pressure we're gonna

have so consider this water this jug on

this side actual pressure voltage now

over here when I pull the plug it's

gonna run through here that's amperage

or current as electricity starts to run

it's gonna do some work it's gonna do

the work in the form of resistance ohms

of resistance now our wheel here that

could be a fuel pump that may be a wiper

motor but it's actually gonna do some

work so when I pull the plug

we'll see the actual voltage start to go

down the current will slow down

eventually and the work will stop so

there goes our voltage or current

running it's running our fuel pump when

the voltage starts to go away the

current slows down the fuel pumps not

going to work anymore three terms and we

can look at them at the DV om that's

voltage current and resistance all right

let's get that DV om digital volt

ohmmeter in your hand and make you feel

comfortable with it it's pretty simple

right here it starts out with volts now

this first one is AC voltage some wheel

speed sensors maybe some pickups in the

distributor but most of our cars DC volt

so I'm gonna come over to DC volts a

little dotted with the wavy line we can

do two things we can come right across

the battery here with the positive to

the negative and we can look at the

pressure you remember that actual

pressure the water in that container

that's voltage it's got twelve point

three five volts of pressure or we can

go to the circuit itself I can come from

the negative and go right up to the

headlight and you can see there it's

about eleven point six zero right to the

headlight so you can go to a point or

you can go across the circuit next one I

want to look at ohms of resistance

that's the Omega the Horseshoe here now

ohms of resistance that water wheel that

water wheel had a resistance value this

light bulb has a resistance value the

electricity is gonna go in it's gonna

light it up in the form of work and we

can measure that so I can go across one

side of this and I'll go inside and I'll

touch the other side and if I can get a

contact here between

the two sides you can actually see

there's gonna be a ohm value inside of

here there it goes

so the light bulb hat is around two ohms

flicking back I'm wiggling a little bit

but it's gonna change ohms point six

point seven that's the actual element

inside of there that's the ohms of

resistance now last but not least is

amperage amperage is that current flow

when that water was running we were

getting current flow that's gonna light

the lights in the form of work so if I

switch my meter over here two amps now

it's very important to shunt the meter

why am i shunting the meter because it's

fused I want to protect the meter inside

because the amps are gonna run through

the meter in order to run through the

meter that means we're gonna have to

open up the circuit so I'm gonna come up

here to the light bulb light I'm gonna

disconnect it and the light bulb goes

out and then what's gonna happen as I

come through I'll take one connection to

one side and I'll take the other one to

the other and we'll go ahead and

complete the circuit and we can look at

2.3 around 2 amps of electricity it's

taken to run to those light bulbs so

with volts amps and ohms of resistance

you can be pretty proficient with that

DV om and get out work on your car find

out if you have any electrical gremlins

that you want to fix

don't forget follow us on Twitter look

us up on Facebook and social media

thanks for watching