Analog and Digital

Someone else will have to describe it for communications and audio.

Not to over simplify it--Digital is a yes or no--and when an electrical signal(doesn't matter what it's characteristics are) is present, it represents a 1 or yes and when it is gone a 0 or no.

Analog--The characteristics of the electrical signal matter --0 to 10 volt signal: 0=zero, 5= 50%, 10=100%, and so on. Current is some times used: 4-20 mA(Milliamps) Same thing is true and can be based on percentage. It can control a motors speed--4mA or less the motor is stopped--As you increase the mA signal the motors drive will increase it's speed. It can be used for positioning valves or cylinders.

There is a lot more to it than this.

Each digital input signal to a gate is either high or low; base 2. The output from the gate depends on the inputs and the type of gate (AND, OR, NAND, XOR). Example output from AND gate is high if both Inputs are high, low if not. But output from an OR gate is high if either Input is high. The output from gate 1 can become the Input to Gate 2, etc, etc, etc.

An analog signal has a range of values (low to high) from 4-20 mA. Example (valve) position zero (closed) represent 4 mA while (valve) position 100% (fully open) represents 20 mA. The transmitter for this analog signal when calibrated can take any value between 4 and 20 mA and convert it to a (valve) position within its range (between 0 and 100%).

Signals outside the range (<4 mA or >20 mA) are out of range. The transmitter will report "BAD DATA". An "Instrumentation and Control" technician will need to be called to service the analog signal in this case. The analogy between the electronic signal and the mechanical valve position is not making sense (for example).

You may say, o.k. so analog is better then? Remember that today discrete gates (digital) are seldom used in practice. However an integrated circuit containing 1 million or more gates on a silicon chip the size of a finger nail can be programmed and used making digital signal processing practical.

Both methods (analog and digital) are widely used today.

When referring to signals, use the word electronics, not electricity.

When referring to power, use the word electricity, not electronics.

Power supply and signal source are very different concepts.

Pleaasee, get out your school books and start reading!

Analog and digital refer to the two ways electricity can what?

a) Be measured by a VOM

b) Be used in a control circuit

c) Both of the above

d) None of the above

All of your posts sound like questions from a basic technical knowledge aptitude exam usually given by an employer.

If you are going to use the answers you gain here to just "fill in the blanks" of a test so you can be considered for an on-the-job training program or advanced courses offered by your employer.....Don't do it! You will be "found out" in a hurry. Hopefully before you can injure yourself or a co-worker.

At the very least, take some courses at a local college or technical school in the disciplines required for whatever it is you are trying to pursue. Or buy some books and learn some basics so you won't have to ask for the answers to such rudimentary questions.

Good general reference books to have on hand:

"Bushsbaum's Complete handbook of practical electronic reference data"

http://www.alibris.com/search/books/qwork/833511/used/Buchsbaum's%20Complete%20handbook%20of%20practical%20electronic%20reference%20data

"Practical electrical wiring"

http://www.amazon.com/Practical-Electrical-Wiring-Residential-Commercial/dp/0971977917

"Machinery's handbook"

http://www.amazon.com/s/?ie=UTF8&keywords=machinery%27s+handbook&tag=googhydr-20&index=aps&hvadid=1109102201&ref=pd_sl_9bh0gjicgc_b

I see you're still in a prankish mood. So my answer is: True....provided.

Please enroll in a vocational school or an apprenticeship program. If you can't even answer the most basic question on electrical theory, you pose a very real threat to ypourself, your co-workers, and the facility where you are employeed.

That's a bit dramatic, even for a Mississippi boy. 'Sides that, the question (and the other one) is not asking about "electrical theory."

hi sir
just to add something:
if you have 10vdc input and you want to control the output from 0-10vdc you can do it analog or digital.
analog is to place rheostat in the line, more ohms less output.
digital is to change the duty cycle?
duty cycle is to change the timing of the switching ''on-off''
when the duty cycle is 10% that mean the ''on'' time is 10% and ''off '' time is 90% and you will get output 10% of the input voltage.
when the duty cycle is 50% it means half the time ''on'' and half the time ''off '' and you will get output 50% of the input voltage and so on.
this digitally switching is occur at very high frequency.
when you switch on the input, the output will go from 0v to 10v quickly.
when the duty cycle is 10%, the switching OFF will occur faster and the output will cutoff when the input reach only 1v, so the output will be 1v and so on.

STOP POSTING YOUR HOMEWORK QUESTIONS HERE!

STOP ANSWERING THEM FOR HIM. THIS PERSON HAS POSTED NUMEROUS STUDENT QUESTIONS IN THE PAST WEEK IF IT CONTINUES TO SUCCEED, THEIS FORUM WILL GET FLOODED WITH STUDENTS TRYING TO GET THEIR WORK DONE FOR THEM AND WILL BECOME USELESS FOR ANYONE ELSE.