Electricity for Amateur Radio

How Much Electricity is Moving Electricity is like punches How many electrons are moving? How many punches are thrown? The number of electrons flowing is the current – more current more Punches (T3A-03) We have given you “Ample” warning Current is measured in “Amperes” (T5A-01)

How Hard do You Punch? Volt We call it “Electromotive Force” We Measure Electromotive Force in Volts (T5A-11) When electricity punches hard It will give you quite a “Volt”

Power (Number of Punches X Force of the Punch) More Punches – More Force More Power What term describes the rate at which electrical Energy is used? Power (T5A-10) We measure electric power in Watts because Lots of punches and lots of force And you too will wonder “Watt hit Me?” (T5A-2)

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 Voltage Current If you have two pieces of the pie (Watts) If you have two pieces of the pie You can always get the rest. If you have two little pieces Multiply them Together to get the big piece Voltage Current (Amperes) Power = Voltage X Current (T5C-08)

What If I Have the Big Piece and a Little Piece? You divide the big piece by the little Piece 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 (T5C-09) What do we have? 13.8 X 10 = 138

Another Factor In Electricity Flow How Much Resistance is Holding Current Back

Resistance Has Units of Ohms “Ohm” My How do I explain Resistance?

Introducing the Ohm’s Law Pie Voltage Current Resistance Did Somebody Say Lawyer? 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 Current Typical for Battery Voltage is steady And does not change Current Flows One Way Called Direct Current (DC) Like the Outlet in your house Voltage goes up and down Like a wave Current Changes direction each time 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 Changes Sign 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 just Call 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 Trancievers Use Direct Current That’s why you can hook them to A battery or plug into a cigarette lighter Most run on 12 volts

Connecting a Mobile

Powering Your Base Station Radio Battery Tender to Keep your Battery charged Battery to Power Your Radio Plugs into your wall outlet Puts out DC power for Your radio. Can also run your Base station with A plug in power supply

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. Slow charger with even Remotely good ventilation And I just can’t see the Hydrogen issue. A $7 to $10 battery box and some duct Tape will keep most kids out.

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 output Voltage 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 the Charger 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 Tube Videos 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 use These) The old carbon-zinc and alkaline Batteries 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 through are called conductors. Like the Copper Wire in your House (most metals are conductors)

Some Things are Hard Things that stop electric Signals are insulators (Things like plastic and glass 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 control Amplitude)

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 plates Insulator The Capacitor is two electrical plates Separated by an insulator. (T6A-05) It can accumulate charges on the Plates and store energy in an Electric field. (T6A-04) The capacity to store energy in an Electric field is called “Capacitance” (T5C-01)

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 Component The Inductor An Inductor is usually composed of a Coil of wire. (T6A-07) The ability to store energy in a magnetic field is called “inductance” (T5C-03) The type of component that stores energy in a magnetic field is an inductor (T6A-06) They store energy in a magnetic field

What is the Name of the Duck? Henry Henry The Basic Unit of Inductance Is the Henry! (T5C-04)

Using Capacitors and Inductors Together Inductors and Capacitors Work together to let you Tune an electric circuit To 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 an electromagnet A switch controlled with an electromagnet is Called a relay (T6D-02)

Don’t Blow a Fuse Fuses Protect other electrical components from current overload (T6A-09)

Changing the Voltage 120 volts is just too much For your computer. Transformers are used to increase or decrease voltage

The Semi-Conductor A conductor will allow electricity To go through An insulator will not allow Electricity to go through A semiconductor will allow Electricity to go through only under Certain conditions. An example is a diode that allows electricity to flow in only one Direction.

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! Your Turn (T6B-06)

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 in Another circuit do.

What can I do with that? I can use a transistor to amplify a signal Or even turn it off all together.