Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Bill Never
 
Posts: n/a
Default Amps and Ohms and Volts?

Hello,
I have a Bose car stereo that has a 40 watt amp for each speaker(4
speakers).
I currently have 2 ohm speakers. I want to place the speaker with 4
ohm speaker.

My question is will this work?

(R)Resistence x (I)Amperage = (V)voltage

2x40=80
Bose Speakers = 2 ohm (Resistence)
Amplifier = 40 AMPs ( Intensity - Current/Amperage)
Volts = 80 (Voltage)

4x25=100
After Market Speaker = 4 ohm
Amplifier = 25 AMPS
Volts = 100

or would it be

4x80=100
After Market Speaker = 4 ohm
Amplifier = 80 AMPS
Volts = 320


Thanks in Advanced, Alex


---------------------------------------------------------------------------------------------

Ohms Law is a mathematical equation that shows the relationship
between
Voltage, Current and Resistance in an electrical circuit. It is stated
as:

V = I x R

R = V / I

I = V / R


Whe

V = Voltage
Voltage is an electric potential difference between two points on
a conducting wire.
Voltage is measured in volts. Voltage comes from various sources.
Two examples of these sources are batteries and electrical outlets


I = Current (I stands for INTENSITY) AMPS
Current is measured in amps.
Current is charged particles which flow from the voltage source
through
conductive material to a ground


R = Resistance (ohms)
Resistance is the opposition that a material body offers to the
passage of an
electric current. Resistance is measured in ohms.
Examples of items with resistance are light bulbs, hair dryers,
toasters.



Ampere :
a unit of electric current equivalent to a steady current produced
by one volt applied across a resistance of one ohm.

Watt: the metric unit of power equal to the work done at the rate of
one joule
per second or to the power produced by a current of one ampere across
a potential
difference of one volt.

Volt: the meter-kilogram-second unit of electrical potential
difference and electromotive
force equal to the difference in potential between two points in a
wire carrying a constant
current of one ampere when the power dissipated between the points is
equal to one watt.

Joule: a unit of work or energy equal to the work done by a force of
one newton acting through
a distance of one meter.

Newton: the unit of force in the metric system equal to the force
required to impart an
acceleration of one meter per second per second to a mass of one
kilogram.

Electonvolt: (symbol: eV) is a unit of ENERGY. One eV is equal to the
amount of energy one
electron acquires by accelerating (from rest) through a potential
difference of one volt.
It is usually used as a measure of particle energies although it is
not an SI
(System International) unit.
The SI unit for energy is the JOULE. 1 eV = 1.602 x 10-19 joule.

Volt: is the SI unit of ELECTRIC POTENTIAL, potential difference or
e.m.f. (electro motive force) defined as the difference of potential
between two points
on a conductor carrying a constant current of one ampere when the
power dissipated between
the points is one watt. It is named after Alessandro Volta (1745-1827)

Watt: A Watt is a unit of power, defined as the rate of energy
transferred [per second].
The energy is usually defined as Joules; therefore, one Joule per
second is one Watt.
When measuring heating effects, a unit of thermal energy known as a
calorie is used.
One calorie is 4.184 Joules.
Materials have a property called thermal capacity or specific heat.
This is a measure
of how many calories are needed to raise 1.0 gram of the material one
degree Centigrade.
The thermal capacity of water at 15 deg. C is 1.0 calorie. That is
4.184 Joules or
4.184 Watt-seconds. The entire energy could be transferred to the
water in one millisecond
at a rate of 4184 watts to produce the same temperature rise of one
deg. C.

The thermal capacity of materials changes slightly with temperature
primarily due to
changes in density, and very dramatically at phase transitions, such
as ice melting
and water boiling.

The specific heats of a few selected elements at 25 deg. C a

Material Specific Heat at 25C
Aluminum 0.2154
Gold 0.0305
Hydorgen 3.42
Xenon 0.0379

Horsepower: is the imperial (British) unit of power, now replaced by
the
watt - the new SI unit. One horsepower is the work done at the rate of
550 foot-pounds per second and it is equivalent to 745.7 watts.
Horsepower was first
used by James Watt, who employed it to compare the power of steam
engines with
that of horses.


Note:
It may help to realize that the electric potential is a property
associated with the field
in the space (i.e. in-between the capacitor plates conected to a
battery), while the
energy is associated with the particle you place into that field (and
it depends on the
particle).

All the parameters are in SI units. e.g: e (in Joules), m (Kilograms)
and
c (meters/second). However you can convert into your favourite units,
taking into account the proper relations in between.
  #2   Report Post  
Rheilly Phoull
 
Posts: n/a
Default Amps and Ohms and Volts?


"Bill Never" wrote in message
om...
Hello,
I have a Bose car stereo that has a 40 watt amp for each speaker(4
speakers).
I currently have 2 ohm speakers. I want to place the speaker with 4
ohm speaker.

My question is will this work?

(R)Resistence x (I)Amperage = (V)voltage

2x40=80
Bose Speakers = 2 ohm (Resistence)
Amplifier = 40 AMPs ( Intensity - Current/Amperage)
Volts = 80 (Voltage)

4x25=100
After Market Speaker = 4 ohm
Amplifier = 25 AMPS
Volts = 100

or would it be

4x80=100
After Market Speaker = 4 ohm
Amplifier = 80 AMPS
Volts = 320


Thanks in Advanced, Alex


--------------------------------------------------------------------------

-------------------

Ohms Law is a mathematical equation that shows the relationship
between
Voltage, Current and Resistance in an electrical circuit. It is stated
as:

V = I x R

R = V / I

I = V / R


Whe

V = Voltage
Voltage is an electric potential difference between two points on
a conducting wire.
Voltage is measured in volts. Voltage comes from various sources.
Two examples of these sources are batteries and electrical outlets


I = Current (I stands for INTENSITY) AMPS
Current is measured in amps.
Current is charged particles which flow from the voltage source
through
conductive material to a ground


R = Resistance (ohms)
Resistance is the opposition that a material body offers to the
passage of an
electric current. Resistance is measured in ohms.
Examples of items with resistance are light bulbs, hair dryers,
toasters.



Ampere :
a unit of electric current equivalent to a steady current produced
by one volt applied across a resistance of one ohm.

Watt: the metric unit of power equal to the work done at the rate of
one joule
per second or to the power produced by a current of one ampere across
a potential
difference of one volt.

Volt: the meter-kilogram-second unit of electrical potential
difference and electromotive
force equal to the difference in potential between two points in a
wire carrying a constant
current of one ampere when the power dissipated between the points is
equal to one watt.

Joule: a unit of work or energy equal to the work done by a force of
one newton acting through
a distance of one meter.

Newton: the unit of force in the metric system equal to the force
required to impart an
acceleration of one meter per second per second to a mass of one
kilogram.

Electonvolt: (symbol: eV) is a unit of ENERGY. One eV is equal to the
amount of energy one
electron acquires by accelerating (from rest) through a potential
difference of one volt.
It is usually used as a measure of particle energies although it is
not an SI
(System International) unit.
The SI unit for energy is the JOULE. 1 eV = 1.602 x 10-19 joule.

Volt: is the SI unit of ELECTRIC POTENTIAL, potential difference or
e.m.f. (electro motive force) defined as the difference of potential
between two points
on a conductor carrying a constant current of one ampere when the
power dissipated between
the points is one watt. It is named after Alessandro Volta (1745-1827)

Watt: A Watt is a unit of power, defined as the rate of energy
transferred [per second].
The energy is usually defined as Joules; therefore, one Joule per
second is one Watt.
When measuring heating effects, a unit of thermal energy known as a
calorie is used.
One calorie is 4.184 Joules.
Materials have a property called thermal capacity or specific heat.
This is a measure
of how many calories are needed to raise 1.0 gram of the material one
degree Centigrade.
The thermal capacity of water at 15 deg. C is 1.0 calorie. That is
4.184 Joules or
4.184 Watt-seconds. The entire energy could be transferred to the
water in one millisecond
at a rate of 4184 watts to produce the same temperature rise of one
deg. C.

The thermal capacity of materials changes slightly with temperature
primarily due to
changes in density, and very dramatically at phase transitions, such
as ice melting
and water boiling.

The specific heats of a few selected elements at 25 deg. C a

Material Specific Heat at 25C
Aluminum 0.2154
Gold 0.0305
Hydorgen 3.42
Xenon 0.0379

Horsepower: is the imperial (British) unit of power, now replaced by
the
watt - the new SI unit. One horsepower is the work done at the rate of
550 foot-pounds per second and it is equivalent to 745.7 watts.
Horsepower was first
used by James Watt, who employed it to compare the power of steam
engines with
that of horses.


Note:
It may help to realize that the electric potential is a property
associated with the field
in the space (i.e. in-between the capacitor plates conected to a
battery), while the
energy is associated with the particle you place into that field (and
it depends on the
particle).

All the parameters are in SI units. e.g: e (in Joules), m (Kilograms)
and
c (meters/second). However you can convert into your favourite units,
taking into account the proper relations in between.


Don't confuse watts with amps !!
The power rating of speakers is used as a sales point and usually bears
little resemblance to that actually developed, also of course in the average
unit the power developed will vary with the frequency.
You could expect a lower output with a mismatch of the 4ohm speakers.
--
Regards ............... Rheilly Phoull


  #3   Report Post  
Mark D. Zacharias
 
Posts: n/a
Default Amps and Ohms and Volts?

Does not relate directly to speaker sensitivity. Assuming the ohms rating is
correct here, it simply means that less current will flow through the
speaker with a given signal voltage applied. A more efficient speaker will
still be louder regardless of impedance. Some of the most efficient, loudest
speakers ever made were 16 ohms.


Mark Z.

You could expect a lower output with a mismatch of the 4ohm speakers.


--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Rheilly Phoull" wrote in message
...

"Bill Never" wrote in message
om...
Hello,
I have a Bose car stereo that has a 40 watt amp for each speaker(4
speakers).
I currently have 2 ohm speakers. I want to place the speaker with 4
ohm speaker.

My question is will this work?

(R)Resistence x (I)Amperage = (V)voltage

2x40=80
Bose Speakers = 2 ohm (Resistence)
Amplifier = 40 AMPs ( Intensity - Current/Amperage)
Volts = 80 (Voltage)

4x25=100
After Market Speaker = 4 ohm
Amplifier = 25 AMPS
Volts = 100

or would it be

4x80=100
After Market Speaker = 4 ohm
Amplifier = 80 AMPS
Volts = 320


Thanks in Advanced, Alex



--------------------------------------------------------------------------
-------------------

Ohms Law is a mathematical equation that shows the relationship
between
Voltage, Current and Resistance in an electrical circuit. It is stated
as:

V = I x R

R = V / I

I = V / R


Whe

V = Voltage
Voltage is an electric potential difference between two points on
a conducting wire.
Voltage is measured in volts. Voltage comes from various sources.
Two examples of these sources are batteries and electrical outlets


I = Current (I stands for INTENSITY) AMPS
Current is measured in amps.
Current is charged particles which flow from the voltage source
through
conductive material to a ground


R = Resistance (ohms)
Resistance is the opposition that a material body offers to the
passage of an
electric current. Resistance is measured in ohms.
Examples of items with resistance are light bulbs, hair dryers,
toasters.



Ampere :
a unit of electric current equivalent to a steady current produced
by one volt applied across a resistance of one ohm.

Watt: the metric unit of power equal to the work done at the rate of
one joule
per second or to the power produced by a current of one ampere across
a potential
difference of one volt.

Volt: the meter-kilogram-second unit of electrical potential
difference and electromotive
force equal to the difference in potential between two points in a
wire carrying a constant
current of one ampere when the power dissipated between the points is
equal to one watt.

Joule: a unit of work or energy equal to the work done by a force of
one newton acting through
a distance of one meter.

Newton: the unit of force in the metric system equal to the force
required to impart an
acceleration of one meter per second per second to a mass of one
kilogram.

Electonvolt: (symbol: eV) is a unit of ENERGY. One eV is equal to the
amount of energy one
electron acquires by accelerating (from rest) through a potential
difference of one volt.
It is usually used as a measure of particle energies although it is
not an SI
(System International) unit.
The SI unit for energy is the JOULE. 1 eV = 1.602 x 10-19 joule.

Volt: is the SI unit of ELECTRIC POTENTIAL, potential difference or
e.m.f. (electro motive force) defined as the difference of potential
between two points
on a conductor carrying a constant current of one ampere when the
power dissipated between
the points is one watt. It is named after Alessandro Volta (1745-1827)

Watt: A Watt is a unit of power, defined as the rate of energy
transferred [per second].
The energy is usually defined as Joules; therefore, one Joule per
second is one Watt.
When measuring heating effects, a unit of thermal energy known as a
calorie is used.
One calorie is 4.184 Joules.
Materials have a property called thermal capacity or specific heat.
This is a measure
of how many calories are needed to raise 1.0 gram of the material one
degree Centigrade.
The thermal capacity of water at 15 deg. C is 1.0 calorie. That is
4.184 Joules or
4.184 Watt-seconds. The entire energy could be transferred to the
water in one millisecond
at a rate of 4184 watts to produce the same temperature rise of one
deg. C.

The thermal capacity of materials changes slightly with temperature
primarily due to
changes in density, and very dramatically at phase transitions, such
as ice melting
and water boiling.

The specific heats of a few selected elements at 25 deg. C a

Material Specific Heat at 25C
Aluminum 0.2154
Gold 0.0305
Hydorgen 3.42
Xenon 0.0379

Horsepower: is the imperial (British) unit of power, now replaced by
the
watt - the new SI unit. One horsepower is the work done at the rate of
550 foot-pounds per second and it is equivalent to 745.7 watts.
Horsepower was first
used by James Watt, who employed it to compare the power of steam
engines with
that of horses.


Note:
It may help to realize that the electric potential is a property
associated with the field
in the space (i.e. in-between the capacitor plates conected to a
battery), while the
energy is associated with the particle you place into that field (and
it depends on the
particle).

All the parameters are in SI units. e.g: e (in Joules), m (Kilograms)
and
c (meters/second). However you can convert into your favourite units,
taking into account the proper relations in between.


Don't confuse watts with amps !!
The power rating of speakers is used as a sales point and usually bears
little resemblance to that actually developed, also of course in the

average
unit the power developed will vary with the frequency.
You could expect a lower output with a mismatch of the 4ohm speakers.
--
Regards ............... Rheilly Phoull




  #5   Report Post  
El Meda
 
Posts: n/a
Default Amps and Ohms and Volts?

El Meda wrote:

The amplifier will try to keep a constant output voltage, so, if you
use 4 ohm speakers instead on 2 ohm speakers, you will have half the
current across each one of them, or 1/4 the Watts i.e. 10
Watts/channel.


Sorry! it's 1/2 the Watts (20 Watts/channel), not 1/4.
---
Ing. Remberto Gomez-Meda
http://ingemeda.tripod.com/
INGE - Ingenieria Electronica.
Puerto Vallarta, Jalisco, Mexico.


  #6   Report Post  
Bill Never
 
Posts: n/a
Default Amps and Ohms and Volts?

" Don't confuse watts with amps !!
The power rating of speakers is used as a sales point and usually bears
little resemblance to that actually developed, also of course in the average
unit the power developed will vary with the frequency.
You could expect a lower output with a mismatch of the 4ohm speakers.


Okay, This is where I get confused. The car has a 12 volt battery.

1) Does the amp produce 40 amps?
2) Or is it powered by 40 watts?
3) Is the amp limited by the 12 volt battery?

I do not understand the difference between volts and watts/joules? Are
they not the same?

Where and how do volts become watts and vice versa?
  #8   Report Post  
James Sweet
 
Posts: n/a
Default Amps and Ohms and Volts?


"Bill Never" wrote in message
om...
" Don't confuse watts with amps !!
The power rating of speakers is used as a sales point and usually bears
little resemblance to that actually developed, also of course in the

average
unit the power developed will vary with the frequency.
You could expect a lower output with a mismatch of the 4ohm speakers.


Okay, This is where I get confused. The car has a 12 volt battery.

1) Does the amp produce 40 amps?
2) Or is it powered by 40 watts?
3) Is the amp limited by the 12 volt battery?

I do not understand the difference between volts and watts/joules? Are
they not the same?

Where and how do volts become watts and vice versa?


Don't worry about the 12v supply, the amp has it's own internal switching
power supply to produce the required voltages, it likely has + and - 20v or
so rails with 40v between them. The wattage rating on the amp is worthless
marketing puke, just ignore it. You can get a reasonably accurate idea of
the power the amp can produce by measuring the voltage of the supply rails
and multiply it by .75 then calculate it into your speaker impedance with
ohms law but really who cares?


  #9   Report Post  
Jeff
 
Posts: n/a
Default Amps and Ohms and Volts?


"Bill Never" wrote in message
om...
Hello,
I have a Bose car stereo that has a 40 watt amp for each speaker(4
speakers).
I currently have 2 ohm speakers. I want to place the speaker with 4
ohm speaker.

My question is will this work?

Snip

Maybe, maybe not well, do not assume Bose speaker
is two ohm unless you know.
Do not assume Bose amp is 40 W/CH.
I would not without knowing which system it is.
Vehicle?
Year?
You have overlooked the important fact that:
The EQ is done in the amp for both the speaker and
the vehicle.
Jeff


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