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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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#1




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 meterkilogramsecond 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 1019 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 (17451827) 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 Wattseconds. 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 25°C 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 footpounds 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. inbetween 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




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 meterkilogramsecond 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 1019 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 (17451827) 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 Wattseconds. 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 25°C 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 footpounds 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. inbetween 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




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 email 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 meterkilogramsecond 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 1019 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 (17451827) 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 Wattseconds. 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 25°C 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 footpounds 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. inbetween 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




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 GomezMeda http://ingemeda.tripod.com/ INGE  Ingenieria Electronica. Puerto Vallarta, Jalisco, Mexico. 
#6




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? 
#7




Amps and Ohms and Volts?

#8




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




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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