• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.


Not open for further replies.


New Member
Hi every one my name is Shaun im a newbie to electronics
if i ask any really dumb questions pleez dont make fun
of me thatz why im here to ask you guys the smat ones
to hope fully gain some of your knowledge ok.

ok first ???
1. what type of voltage do cars and trucks use say under the dash
to the computer ac or dc
2.if i had 12v power source how would i step it down to say 6v
3.what do resistors do
4.what do transistors do
5. what do diodes do
5. what do capacitors do
and finally cany you explain what a low voltage amplifire does
and this is all pertaining to automotive low voltage
can u explain it so a regular person like me can understand


New Member
Alright, lets see if I can help you out. I'm not quite sure myself on some of the things but I recently just took my first electronics course and I think I might be able to explain some of the things to you.

1) I believe that the car uses dc current under the dashboard. I just figured that since the car battery itself is DC, then all the current going through the car must be DC. At least in all the electrical components.

2) The easiest way to convert 12v to 6v would be to either buy one at Radio Shack, or build a circuit with a series of resistors to bring the voltage down. I'm not sure how to build that circuit but if you type in into any search engine, then they should guide you the rest of the way.

3) A resistor is a circuit element just like a transistor, diode, or capacitor. However a resistor basically disisipates electrical energy meaning that current flows from the positive end to the negative end. This dissipation resists the flow of electic current, thus giving you the ability to raise the voltage in a circuit or bring it down

4) A transistor is a small electronic device that can cause changes in a large electrical output signal by small changes in a small input signal. That is, a weak input signal can be amplified (made stronger) by a transistor. For example, very weak radio signals in the air can be picked up by a wire antenna and processed by transistor amplifiers until they are strong enough to be heard by the human ear. A transistor consists of three layers of silicon or germanium semiconductor material. Impurities are added to each layer to create a specific electrical positive or negative charged behavior. "P" is for a positive charged layer and "N" is for a negative charged layer. Transistors are either NPN or PNP in the configuration of the layers. There is no particular difference here except the polarity of voltages that need to be applied to make the transistor operate. The weak input signal is applied to the center layer called the base and usually referenced to ground which is also connected to the bottom layer called the emitter. The larger output signal is take from the collector also referenced to ground and the emitter. Additional resistors and capacitors are required along with at least one DC power source to complete the transistor amplifier.


5) A diode is a circuit element with two wires or terminals. it allows electrical current to flow in only one direction and is used for converting alternating current to direct current. basically if you have a sine wave signal, a diode will cut the signal in half only displaying the positive wave to be shown. I've learned that the diode is used a lot in radios because it takes the radio signal and cuts it in half so that the radio itself can identify the carrier frequency. Basically Diodes are an electrical device which are used to isolate current flow by controlling (blocking or passing) its flow.

6) A capacitor is a circuit element that stores electrical energy, kind of like a battery (I can explain it all to you but I think this website does a better job) http://electronics.howstuffworks.com/capacitor.htm

7) I'm sorry but I have no idea what a low voltage amplifire does. I personally have not even heard of one yet.

Anyway I hope this helps a little and if you have any more questions. Please do not hesitate to ask. Enjoy and good luck with what you plan to do with this knowledge. :D


1) DC

2) I assume you mean 12V DC, not AC. Many different methods - as liquidorb mentioned, you can use resistors, however this is an ineffective method for a few reasons (more info later, if you're interested). Other methods are by a "linear regulator" (using transistor or special regulator chip) - this achieves the best regulation, but is inefficient. Otherwise, you could use a "switching regulator" which is more efficient, but gives poorer regulation, and can be electrically "noisy".

3) A resistor provides an opposition to current flow. The higher the value of resistance, the less current will flow (for a given voltage). Resistors follow the formula V = IR (Ohms Law), where V is the voltage across the resistor, R is the resistance (in ohms) and I is the current flow (in amps)

4) A transistor can operate either as a current amplifier, or as a sort of switch. When you inject a small current into the 'base' of the transistor, it allows a proportionally larger current to flow between the 'collector' and 'emitter'. If you increase the current you inject, the transistor can be used to turn parts of a circuit on or off.

5) As liquidorb said, diodes are a 'one-way' valve for electrical current.

6) Capacitors store electrical energy in the form of an electric field between two metal plates. They have the advantage over a battery, of being able to produce very large currents on demand, however, they cannot store nearly as much energy as a battery. Large capacitors are used for smoothing out voltages in DC power supplies, and provide power factor correction in AC applications. Smaller capacitors have many different uses, too many to list here.

Low voltage amplifier?? Not sure what you're talking about - do you mean an audio amplifier (like a stereo)?


New Member
thank you guys very much i am starting to understand voltage better now
the low voltage amplifier i was referring too was the transistor i beleive
thank you very much though


New Member
i no this might sound dumb say i had 3volts and add on a regular resistor how much voltage would i then have and how can you tell what voltage would bring it down to


New Member
Many many years ago I was in the position you are now in. I did not have the benefit of the internet (was not invented yet) to ask questions. Asking older friends was no good as they considered their knowledge top secret.
So, in a way you are lucky.
But, you also ought to try what I did, to find out things by experimenting. That knowledge is much deeper than reading answers here.
Multimeters are very cheap nowadays, get one, you'll need it anyway once you start experimenting. Find out how it works as you can blow it up easily if set to the wrong position.

Get a small battery, some resistors of different Ohm value, a potentiometer and perhaps a small light bulb (to suit the battery).
Start finding out the answers to your questions above, ask here if you are stuck, but TRY for yourself first.
If you do ask questions here, keep in mind that we cannot read your mind nor see what you are doing, so, be as clear as possible. Try not asking too many questions at once.

Stick to simple DC (battery) principles first, when you are fully clued up about resistors start with a diode, then a transistor. These parts are very cheap, you also often can salvage them from older (more than 10 years old) equipment. Learn how to use a soldering iron to get the parts out. The parts in newer electronic equipment are too tiny for useful experimenting.

Only when you got a reasonable good idea how DC circuits work start with AC. Its too confusing otherwise. Perhaps a small transformer would be useful for experimenting with AC. You'll find that only resistors behave exactly the same, the other components behave differently with an AC voltage, the fun is in finding out how and why :wink:


New Member
ShiftPointShaun said:
can a potentiometer amplify voltage
A potentiometer is just a variable resistor. Turn the knob one way, there's more resistance, turn it the other, there's less resistance... this effects the circuit, how much voltage, current, etc. is inputed into it.

So, it doesn't amplify voltage by itself, but can be used in an amplifier to adjust the amount of voltage amplified...


New Member
electronic advice

:D hi shiftpointshaun,

here's my two cents advice, electronics is a wonderful subject especially if your technically minded. "try to learn and do the basics nice and slow" :D :D :D

just by reading what the guys has responded will just give you the idea how it works, but you would still be wondering how it will be actually function, til you do the actual test. you have to have the basic tools like the multimeter (analog or digital), soldering iron and a breadboard. :D


New Member
thanks guyz

You guyz all a big help for me just learning. I wanna
personally thank you all for answering my questions even though they might of been dumb.


New Member
nother question guyz sorry say i want to keep somthin from showin somthin a voltage higer than what i wanted say somthin has the potential
to display .030 volts but i dont want it to go pass .020v would i use a diode also what type and spec. Thankz for readin will be waitin for ur replyz
Not open for further replies.

Latest threads

EE World Online Articles