Electricity for Amateur Radio

How Much Electricity is MovingElectricity is like punches

How many electrons are moving?

How many punches are thrown?

The number of electrons flowing is the current – more current morePunches (T3A-03)

We have given you“Ample” warning

Current is measured in “Amperes”(T5A-01)

How Hard do You Punch?

We call it “Electromotive Force”

When electricity punches hardIt will give you quite a “Volt”

Volt

We Measure Electromotive Force in

Volts(T5A-11)

Power(Number of Punches X Force of the Punch)

More Punches – More Force

More Power

We measure electric power in Watts

because

Lots of punches and lots of force And you too will wonder “Watt hit Me?”(T5A-2)

What term describes the rate at which electricalEnergy is used?

Power(T5A-10)

Lets See If You Were Sleeping

(I’ve given you ample warning)

(This will give you a jolt)

Yup

(T5A-03)

(T5A-11)

(T5A-05)

One More

That’s Right

Electrical Power Leaves You Wondering “WATT” Hit Me.

The Power Pie

Power(Watts)

Voltage Current(Amperes)

(T5C-08)

If you have two pieces of the pieYou can always get the rest.

If you have two little pieces Multiply themTogether to get the big piece

Power = Voltage X Current

What If I Have the Big Piece and a Little Piece?

You divide the big piece by the littlePiece to get the other little piece.

Current = Power / Voltage

(T5C-11)

Now You Try It(T5C-10)

Which part of the pie do we have?

Checking the Answer

Voltage X Current = Power

12 X 2.5 = 30

Another Try

What do we have?

13.8 X 10 = 138

(T5C-09)

Another Factor In Electricity Flow

How Much Resistance is Holding Current Back

Resistance Has Units of Ohms

“Ohm” My How do I explainResistance?

Introducing the Ohm’s Law Pie

Did Somebody Say Lawyer?

Voltage

Current Resistance

As before – if you have two pieces of the pie you can get the third

If I Have the Two Little Pieces I Multiply to Get the Big Piece

(T5D-02)

If I Have a Big Piece and a Little Piece I divide the Big Piece by the

Little(T5D-01)

Lets Try You On It(T5D-03)

Answer

We Can Do It With Numbers

90 / 3 = 30 Ohms

Your Turn

Answer

12 / 1.5 = 8 Ohms

And Another

120 / 80 = 1.5 amperes

Your Turn

Answer

200 / 100 = 2 amperes

Try It With Two Little Pieces

We multiply two little pieces to get the big piece

2 X 0.5 = 1 Volt

Your Turn

Answer

10 X 1 = 10 Volts

Can You Duplicate These Answers?

(T5D-09)

Two Kinds of Electric CurrentVoltage is steadyAnd does not change

Current FlowsOne Way

Typical forBattery

Called Direct Current (DC)

Voltage goes up and downLike a waveCurrent Changes direction each time

Like the Outlet in your house

Called Alternating Current (AC)

Test Question

Did You Get It Right?

How About This One

Answer

The Voltage on Alternating Current Looks Like a Wave

Every Time the Voltage ChangesSign the Current Changes Direction

The number of times the current changes direction in a second is the frequency(in the U.S. its 60 times per second)

Resisting Flow in an AC Circuit has a Special Name

In a DC circuit we justCall it Resistance

It has units of Ohms

“Ohm My”

In an AC circuit we call it “Impedance”

It still has units of “Ohms”

See If You Can Get This.

Most VHF / UHF TrancieversUse Direct Current

That’s why you can hook them toA battery or plug into a cigarette lighter

Most run on 12 volts

Connecting a Mobile

Powering Your Base Station Radio

BatteryTender toKeep yourBattery charged Battery to Power

Your Radio

Can also run yourBase station withA plug in powersupply

Plugs into your wall outletPuts out DC power forYour radio.

Thoughts on Which Way to Go

• We favor the battery– If the power goes out – so does your power

supply

• Some People like power supplies because they fear children will get into batteries or that battery charging will generate hydrogen.

A $7 to $10 battery box and some ductTape will keep most kids out.

Slow charger with evenRemotely good ventilationAnd I just can’t see theHydrogen issue.

What if My Battery Still Goes Dead in an Emergency?

Power Supplies to Provide Nice Even Power

A Bit About Power Supplies

Your household current is AC

But your Radio runs on DC

How does that happen?

A special type of circuit called a “rectifier”

More on the Power Supply Miracle

My household current is 120 volts

My radio needs 12 volts

How did that happen?

The power supply includes a regulator to control the output voltage

Features on Power Supply And Other Places

Not All Power Supplies Are Created Equal

I can buy this for $40 bucks – a battery and charger will cost me $95

Check the spec. – How many amperes will it put out?

A base station draws around 12 to 16 amps when you transmit

Houston – we have a problem!

Don’t Get Snookered

Oh Cool Man!This one has 500 and is just$50

It has 500 what?

Watts – a measure of power

Watts = Voltage * Amperage

This supply is for a computer – its output voltage is about 5 volts – not 12 volts

Some supplies will express output in watts – if they do you have to check outputVoltage and then calculate the amperes

Suggestion

Don’t buy anything less than a 20 amp power supply.

But I’m Going to Run a Baofeng Handheld on Batteries.

Your radio is only good as long as the battery lasts

You can buy extra batteries

And the battery will fit in theCharger without the radio.

Hey I Found this Extra Large Battery on Amazon

Yes – but this bump means it won’t fit on most Baofeng Radios

You can whittle the offending bumps down with a dremel tool – U TubeVideos are available – if you want the hassle.

Here is a Case I Can Put 6 AAA batteries in

Not all batteries are rechargable!

Ni – Metal Hydride (Ni-MH)Are rechargable

Lithium Ion are rechargable(your cell phone and computers useThese)

The old carbon-zinc and alkalineBatteries are not.

Try the Questions

(This is a fancy rechargeable for base stations)

Some Things Are Easier for Electricity to Go Through

Things that let electricity go throughare called conductors.

Like the CopperWire in yourHouse(most metals are conductors)

Some Things are Hard

Things that stop electricSignals are insulators

(Things like plastic andglass are insulators)

Basic Electric Components

The resistor – it resists the flow of electricity

One Use for a Resistor

Variable resistor is called a potentiometer. It can be used control volume(Remember – the height of a wave or amplitude determines how much power is in the wave – resistors can controlAmplitude)

I Bet You Can Get This One

A potentiometer is a variable resistor - what do you think a potentiometer changes?

Another Component

The Capacitor is two electrical platesSeparated by an insulator. (T6A-05)

It can accumulate charges on thePlates and store energy in anElectric field. (T6A-04)

The capacity to store energy in anElectric field is called “Capacitance”(T5C-01)

Insulator

Two Plates Give You the Capacitance for Advertizing

Capacitors

Capacitors are very fair devices

In fact their capacitance is only measure in “Fair Ads” (Farads)

The Basic Unit of Capacitance is the Farad (T5C-02)

Another ComponentThe Inductor

They store energy in a magnetic field

The ability to store energy in a magneticfield is called “inductance” (T5C-03)

The type of component that storesenergy in a magnetic field is an inductor(T6A-06)

An Inductor is usually composed of aCoil of wire. (T6A-07)

What is the Name of the Duck?

The Basic Unit of InductanceIs the Henry! (T5C-04)

HenryHenry

Using Capacitors and Inductors Together

Inductors and CapacitorsWork together to let youTune an electric circuitTo a particular frequency

Of Course No Circuit Would Be Complete without This!

Do You Always Have to Flip Switches by Hand?

You can actually flip a switch with anelectromagnet

A switch controlled with an electromagnet isCalled a relay (T6D-02)

Don’t Blow a Fuse

Fuses Protect other electrical components from current overload (T6A-09)

Changing the Voltage

Transformers are used to increase or decrease voltage

120 volts is just too muchFor your computer.

The Semi-Conductor

A conductor will allow electricityTo go through

An insulator will not allowElectricity to go through

A semiconductor will allowElectricity to go through only underCertain conditions.

An example is a diode that allows electricity to flow in only oneDirection.

Which Way?

You can flow positive to negative

But you have to use electron terms

Anode + Cathode –(note they are in alphabetical order)

How Can You Tell Which End is Which

They put a band or Stripe on the Cathode Side

Checking to Make Sure Your Awake!

(T6B-06)

Your Turn

Did You Get It?

Stripe on the Cowthode Side

The Amazing Transistor

It is made of 3 layers of semiconductor material

It can use the voltage or current in one circuit to control what it will let current inAnother circuit do.

What can I do with that?

I can use a transistor to amplify a signalOr even turn it off all together.