Bob F

Man A says circuit protection devices (e.g. fuses) are sensitive to current. Man B says they are sensitive only to voltage. Who is correct? Man A only. Man B only. both Man A and Man B. neither Man A nor Man B.

Yep, as most of you answered, the other two lamps will be unaffected. Each branch has its own path to ground, so the current in each of the two remaining branches will remain the same, therefore the brightness remains the same.

No, I think it's called the law of averages. You were bound to get one right eventually.

Several lamps are connected in parallel to a voltage source. If one light burns out, all the other lamps: will go out. will get brighter will not be affected. will get dimmer. See the diagram in the post below.

Correct. It's called an open.

Mixed answers on this one. The sum of voltage drops in a series circuit equals the Source voltage (i.e. the battery voltage on a boat). The diagram below shows this a bit clearer. You shouldn't see any volt drop across a fuse or a closed switch because they are basically shorts. If you do see a volt drop across either a these it is a sign of a bad connection which acts as a resistor. The voltage drops occur across the loads, which in this diagram are to two lamps. If the lamps had the same resistance the voltage drop across each lamp would be the same. In the diagram the voltage drops are different, so the lamps must have a different resistance.

I notice that the video has been removed from YouTube, so I didn't get to see it. Wonder why it was removed?

Actually, it might be something I'd consider. It would certainly be a nice change in the pace of life. Not sure how to go about it, though... BF

The sum of voltage drops in a series circuit equals the: voltage across the largest load. voltage across the smallest load. source voltage. shunt circuit voltage.

A break or interruption in an electrical circuit is: an open. a short. a ground. none of the above.

The answer is 12 volts. Well done, again. A parallel circuit has more than one path for current flow, but the same voltage is applied across each branch. If the load resistance in each branch is the same, the current in each branch will be the same. If the load resistance in each branch is different, the current in each branch will be different. If one branch is broken, current will continue flowing to the other branches.

Two identical lamps are connected in parallel to a 12-volt source. The voltage across each lamp is: 12 volts. 6 volts. 4 volts. 2 volts.

You see, I knew you were all atomic boffins. You all answered correctly. I can only blame it on Scotty!!!

Well, you guys are obviously atomic scientist rather than electricians. 80% were correct. Electrons is the correct answer. An atom is like a tiny solar system. The center of the solar system is called the nucleus (like the Sun in our solar system), and it's made up of tiny particles called neutrons and protons. The nucleus is surrounded by clouds of other tiny particles called electrons. The electrons rotate about the nucleus in fixed paths called shells or rings (like the orbit of planets around the Sun). Each atomic particle has an electrical charge. Electrons have a negative charge (-); protons have a positive charge (+); neutrons have no charge, they are neutral. In a balanced atom, the number of electrons equals the number of protons. The balance of the opposing negative and positive charges holds the atom together (like charges repel, unlike charges attract). The positive protons hold the negative electrons in orbit. The centrifugal force of the electrons prevents them being sucked inwards. And within the nucleus, the neutrons cancel the repelling force of the protons, thus holding the atoms core together. BF

Well, we have a 60/40 split between Voltage and Current on this one. The correct answer is Voltage. Voltage is electrical pressure, a potential force or difference in electrical charge between two points. It can push electrical current through a wire, but not through its insulation. Voltage is measured in volts (V). One volt can push a certain amount of current. two volts twice as much, and so on. A voltmeter measures the difference in electrical pressure between two points in volts. Current is the actual flow of electrons in a wire. Current flows in a wire pushed by a voltage. Current is measured in Amperes (A), or Amps for short. An ammeter measures current in amps. Resistance opposes the flow of current, so it slows the flow of current. Every electrical component or circuit has resistance. Resistance is measured in ohms. A special meter, called an ohmmeter, can measure the resistance of a device in ohms when no current is flowing. The way I visualize the relationship between voltage, current and resistance is to think of a tank of water with a pipe attached to it, and a tap somewhere along the pipe. The tank of water represents the voltage (potential energy). The higher you lift the tank, the greater its potential energy will be, and therefore faster the water (current) will flow out of the pipe. The tap represents the resistance. The more you close the tap (increase resistance), the slower the water will flow. VOLTAGE IS PRESSURE. CURRENT IS FLOW. RESISTANCE OPPOSES FLOW. BF

Ask Norm Abraham. He uses them all the time on New Yankee Workshop. At least Jonathan Ross says he does.

And a slightly tougher one. I sense there's a few of you out there that want a tougher workout. An atom which loses or gains one electron is called: Balanced. An element. A molecule. A charged particle or ion.

Here's a additional question related to Q1 for those that want to try a deeper question. The particles that orbit around the center of an atom are Electrons. Molecules. Nucleus. Protons

The force that causes electrons to flow through a conductor is known as: the power. the current. the voltage. the resistance.

76% voted + to -. 20% voted - to +. 4% voted randomly. The correct answer is positive to negative for Conventional Flow Theory. Unfortunatlely, there are two theories to describe current flow. The Conventional Theory, commonly used for automotive and marine electrical systems, says that current flows from + to -. Electron Theory states that current flows from - to +. Electron theory is the modern theory that is used in electronics and semiconductors. It is actually the true direction of current flow, and is important when understanding the operation of electronic devices like diodes and transistors. Conventional Theory stems from the early experimenters who at that time did not have the knowledge of atoms and electrons. The automotive inductry still uses conventional theory, partly from history but also because the direction of current flow actually makes no difference to the three measurable units of electricity: voltage, current and resistance. So, now that you are thoroughly confused, it can only get better from here.

The conventional theory of current flow says that current flows: Randomly. Positive to negative. Negative to positive. None of the above.

OK, I'll put you out of your misery. I boobed!! It's actually wire brush and baking soda. Which is why the votes were split 50-50. Mix one part baking soda with four parts water. then brush onto the terminals and leave to fizz away for 10 mins. If the fizzing stops and there still a bit a corrosion left, add a little more water and scrub the remainder off with the wire brush. Clean off with a paper towel until dry and then coat the terminals with vaseline. That's the end of the battery quiz for now. If you are still up for it, we'll now move on to some basic electrics/electronics and using a multimeter, next.

What is the most effective method of removing corrosion from battery terminals? Scrub them with a wire brush. Spray with WD40. Wash with a mixture of Baking Soda and water. Rub with vaseline.

The correct answer is 1.270, so congratulations to those that researched the answer. ~1.270 is the Specific Gravity for a fully charged cell. 1.835 is the SG for pure Sulphuric Acid. 1.000 is the SG for pure water. To verify if a battery is worth keeping, check the SG of each cell. If one or more cells differ by more than 50 points (0.050) the battery is defective and should be replaced. If the SG of all of the cells are over 1.225 and the variation between cells is less than 50 points (0.050), the battery can be tested on full load to more thoroughly check that it can handle a real load. To test the battery under load, first check it without a load. Simply turn the engine on (with all auxilliaries turned off) and put a Multimeter across the two terminals of the battery. You should be ~14.4 volts. Next turn on all the auxilliaries that draw the most current (like windscreen wipers, flood lights, radar, pumps, etc) with the engine still running. Now check the voltage across the terminals of the battery again. If the voltage is between 12.2 volts and 14.4 volts the battery is ok. cheers BF