Some Technical Questions About Electricity, Amps and Speakers

zanshin777

New member
I’m trying to understand some electrical concepts related to working of guitar amps and magnets and I have some questions.


1) Title : Signals

I read that “Impedance depends on Frequency Of Signals” What does that mean? Do Signals have Impedance in themselves?



2) Title : Tubes

It’s said Cathode is charged with “-“ and Anode is charged with “+”. When filament is heated electrons flow from cathode to anode. When this movement is done cathode should be charged with “+” and anode should be charged is “–“ Isn’t it?

It’s said then electrons in the anode go “-“ terminal and after that “+” terminal of the battery. When the anode is charged with “-“ how those electrons go “-“ terminal of the battery? (Because “-“ push “-“)


3) Title : Signals

Are Current and Signals the same thing? How does current include information about signals in it?


4) Title : Amps

When the amp is off does an electric guitar still send signals to the amp when played?


5) Title : Electricity

How are Electrical devices activated when we pushed the “on” button?


6) Title : Speakers

Are diaphragm, speaker cone and the driver the same thing?


7) Title : Electric And Magnetic Field

“Therefore, they are inter-related in a field called the electromagnetic field. In this field, the electric field and the magnetic field move at right angles to each other However, they are not dependant on each other. They may also exist independently. Without the electric field, the magnetic field exists in permanent magnets and electric fields exist in the form of static electricity, in absence of the magnetic field.

Wherever there is electricity, there also electric and magnetic fields, invisible lines of force created by the electric charges. Electric fields result from the strength of the charge while magnetic fields result from the motion of the charge, or the current.”

These two paragraph contradict each other? Don’t they?


8) Title : Usage Of Capacitors


Power Supply Smoothing : This is the easiest and very widely used application of a capacitor. If you stick a big beefy electrolytic capacitor (the bigger the better), it will fill in all the gaps created by rectifying an AC form, to create a relatively smooth DC. It works by repeatedly charging during the peaks, and discharging during the gaps. However, the more load you put on it, the quicker it wil drain the capacitor and the more ripple you’ll get”

8.1) Why there are gaps and peaks whilst rectification?


Timing : If you supply power to a capacitor through a resistor, it will take time to charge. If you connect a resistive load to a capacitor, it will take time to discharge. The key thing to understand here about timing circuits is that capacitors appear as though they are shor circuit while they are charging, but as soon as they are charged, they appear to be open circuit.”

8.2) How do capacitors do the Timing job?


Filtering : If you pass DC through a capacitor, it will charge and then block any further current from flowing. However, if you pass AC through a capacitor, it will flow. How much current flows depends on the frequency of the AC, and the value of the capacitor.
A filter capacitor is an electronic component that removes voltage or signal spikes in electronic circuits. Capacitors are used as filter devices due to their ability to absorb and effectively store electrical charges at predetermined values.”


8.3) When capacitors are charged don’t they transmit the current?
 
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Re: Some Technical Questions About Electricity, Amps and Speakers

Wow, that's quite a bunch of questions, if you really wanna understand it all in depth you'd better study physics ;). But here we go with a small attempt at some of the questions:

I’m trying to understand some electrical concepts related to working of guitar amps and magnets and I have some questions.


1) Title : Signals

I read that “Impedance depends on Frequency Of Signals” What does that mean? Do Signals have Impedance in themselves?

I think what was meant here is that impedance can depend on the type of signal you use. Usually it depends on the frequency of the signal. Let's talk about the impedance of your tone knob (and its capacitor). For low frequencies you get low impedance (that is little signal is lost, low resitance), for higher frequencies more signal is lost (more resistance).

In general all components we use have some change in impedance dependend on the frequency of the signal applied to them.

2) Title : Tubes

It’s said Cathode is charged with “-“ and Anode is charged with “+”. When filament is heated electrons flow from cathode to anode. When this movement is done cathode should be charged with “+” and anode should be charged is “–“ Isn’t it?

No, it's like we have 10.000 times a minus on the cathode and 10.000 times a plus on the anode and one - decides to fly over. In the end we have then 9.999 minus left on the anode and 9.999 plus left on the cathode.

It’s said then electrons in the anode go “-“ terminal and after that “+” terminal of the battery. When the anode is charged with “-“ how those electrons go “-“ terminal of the battery? (Because “-“ push “-“)

I'm not sure I get it, but I guess the answer to the last question also answers this one. Let's view it this way: you have one minus traveling and it always seeks the point the most plusses are at.

3) Title : Signals

Are Current and Signals the same thing? How does current include information about signals in it?

A signal can be both in current and voltage, actually it is most accurate to say it is both usually. In our preamps (SS or tube) we usually multiply the voltage part of the signal, while in our power amps we usually mulitply the currents.

No matter if we talk about voltage or current, the important thing for us musicians is the so called frequency content. That is what we call our signal. The current or voltage goes up and down (or back and forth, dependent on how you look at it) from 20 to 20.000 times a second (the audible range), dependend on what we play. This is what we call signal. (It is actually more complicated, because we always have a combination of multiple frequencies at the same time when making music. But it is easier to think about it as just one frequency).

4) Title : Amps

When the amp is off does an electric guitar still send signals to the amp when played?

Yes, current is still induced in the pickups, just not amplified.

5) Title : Electricity

How are Electrical devices activated when we pushed the “on” button?
The circuit is broken by the on/off button, when we turn it on the circuit is complete allowing current to flow again.


6) Title : Speakers

Are diaphragm, speaker cone and the driver the same thing?
Don't know this one, google it I'd say


7) Title : Electric And Magnetic Field

“Therefore, they are inter-related in a field called the electromagnetic field. In this field, the electric field and the magnetic field move at right angles to each other However, they are not dependant on each other. They may also exist independently. Without the electric field, the magnetic field exists in permanent magnets and electric fields exist in the form of static electricity, in absence of the magnetic field.

Wherever there is electricity, there also electric and magnetic fields, invisible lines of force created by the electric charges. Electric fields result from the strength of the charge while magnetic fields result from the motion of the charge, or the current.”

These two paragraph contradict each other? Don’t they?

No, the complicated thing is this: a charge that does not move does produce an electric field. When it starts moving (that is what we usually call turning on the electricity) then it will also create a magnetic field.


8) Title : Usage Of Capacitors


Power Supply Smoothing : This is the easiest and very widely used application of a capacitor. If you stick a big beefy electrolytic capacitor (the bigger the better), it will fill in all the gaps created by rectifying an AC form, to create a relatively smooth DC. It works by repeatedly charging during the peaks, and discharging during the gaps. However, the more load you put on it, the quicker it wil drain the capacitor and the more ripple you’ll get”

8.1) Why there are gaps and peaks whilst rectification?
You shoukl view a capacitor as a large storage place for electrons. AC voltage basically means this: the voltage goes from positive to negative 50/60 times per second. First we change this via diodes (or tube rectifiers) to make shure only the + part passes, the minus part is then taken, flipped around by another diode(/tube rec) and these two are brought together again. What you have then is a landscape of bumps (look at this picture). What the capacitor does is this: when there are a lot of minusses (the peaks) it takes some charges in its reservoir, cause the peak to be lowered a little. When the valleys of the signal come it releases charges so the valleys get filled, in effect you get a pretty flat signal. The bigger the capacity, the bigger the amount of charges it can adsorb and pour into these valleys, so the smoother it gets.


Timing : If you supply power to a capacitor through a resistor, it will take time to charge. If you connect a resistive load to a capacitor, it will take time to discharge. The key thing to understand here about timing circuits is that capacitors appear as though they are shor circuit while they are charging, but as soon as they are charged, they appear to be open circuit.”

8.2) How do capacitors do the Timing job?

I quess the simplest explenation goes like this. The value of the capacitor determines how many charges it can hold. The more it can hold the bigger the value. The value of a resistor determines how much of these charges get used up. The higher the value, the more it uses up. So together these two determine how quick all the charges can get out of the capacitor, or for that matter get into it.

Filtering : If you pass DC through a capacitor, it will charge and then block any further current from flowing. However, if you pass AC through a capacitor, it will flow. How much current flows depends on the frequency of the AC, and the value of the capacitor.
A filter capacitor is an electronic component that removes voltage or signal spikes in electronic circuits. Capacitors are used as filter devices due to their ability to absorb and effectively store electrical charges at predetermined values.”


8.3) When capacitors are charged don’t they transmit the current?
Nope, only when you let the current flow the other way again they can give current. View it as a full barrel, when filled, the only direction of flow then is out of it again.
 
Re: Some Technical Questions About Electricity, Amps and Speakers

I can recommend this YT channel:
https://www.youtube.com/channel/UCuR4hQTXkG_KxozLxwPzEjQ

This video will be a good starting point:
 
Re: Some Technical Questions About Electricity, Amps and Speakers

I've been reading related concepts for a while from different sources. Most probably short answers will suffice for me.
 
Re: Some Technical Questions About Electricity, Amps and Speakers

These guys have you set in the right direction, but I will add, current flows from positive to negative and electrons flow in the opposite direction, from negative to positive.
 
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