Speaker Impedance 50OHM

[fuzzzy]

replacement speaker mylar 50 ohm resistor

HI,

I'm repairing an electronic device, it has a loudspeaker to change.

It seems a Mylar speaker. 50mm diameter. there is write on it: 0.2W 50F 50 OHM

I found on catalogues similar speaker with same power but i can only find max 22 OHM.
Can I use modify this speaker to fit my device?? can i use 22 OHM in your opinion?
Where can i Find 50 OHM speaker??

Thanks

**broken link removed**

 

[gelidude]

mylar speaker 50 ohm

50 ohm value is the impedance of the speaker. and as we know, to get maximum power transfer between the amplifier and the speaker, the two should have equal impedance. using anything other than that will degrade the performace of your audio system. the 22ohm speaker will work but you would not get the same sound quality like before. the 0.2 watts rating may no longer be a sufficient replacement. but if you really can't find a 50 ohm speaker, you can use the 22 ohm speaker but insert in series with the speaker leads a 22 or 27 ohm resistor to prevent burning out the speaker's voice coil and also to make the the amplifier "see" a 50 ohm load ( 22 + 27 = 49 ohm, nearly 50 ohm ). make sure the resistor you use is rated at 0.25 watts or higher.

Added after 2 minutes:

Oh yeah, you can also use a matching transformer to match the 50 ohm output impedance of the amplifer and the 22 ohm speaker.

Added after 7 minutes:

50 ohm value is the impedance of the speaker. and as we know, to get maximum power transfer between the amplifier and the speaker, the two should have equal impedance. using anything other than that will degrade the performace of your audio system. the 22ohm speaker will work but you would not get the same sound quality like before. the 0.2 watts rating may no longer be a sufficient replacement. but if you really can't find a 50 ohm speaker, you can use the 22 ohm speaker but insert in series with the speaker leads a 22 or 27 ohm resistor to prevent burning out the speaker's voice coil and also to make the the amplifier "see" a 50 ohm load ( 22 + 27 = 49 ohm, nearly 50 ohm ). make sure the resistor you use is rated at 0.25 watts or higher.

 

[neils_arm_strong]

speaker resistance

gelidude is right.You can use the 22ohm speaker with appropriate matching network.

 

[Kral]

50 ohm speaker unique

fuzzzy,
Modern electronic device designs do not match the power output stage impedance to the load impedance. The output stage is treated as a voltage source with sufficient current capability to provide the required output power. Impedance matching per se is not the issue. If the efficiency of the new 22 Ohm speaker is the same as the old 50 Ohm speaker, then you need to supply a current of SQRT((50/22)) times the current required by the old 50 Ohm speaker to get the same maximum output. This means that the total resistance (including the speaker resistance) must be 50XSQRT((22/50)) = 50 X .6633 = 33.2 Ohms (an additional series resistance of 11.2 Ohms). Before proceding, you need to answer the following 2 questions:
.
Will the output stage will be damaged by the lower resistance load?
.
Is the output stage capable of supplying enough output current to give the same maximum output as with the 50 Ohm load without distortion due to current limiting?
.
If the answer to the 1st question is "Yes", or if the answer to the 2nd question is "NO", then you have no choice but to add a 28 Ohm serieas resistance, resulting in 50 Ohms total, and be satisfied with a lower maximum power output.
.
If the efiicency of the new speaker is not the same as the old speaker, then you will need to adjust the series resistor accordingly, to compensate for the different efficiency.
.
Before purchasing the new speaker, I would try loading the output stage with a variable resistor load and determine the load resistance at which the output stage starts to current limit.
.
If the device is battery operated, then using the 11.2 Ohm series resistor will result in a higher battery drain.
Regards,
Kral

 

[fuzzzy]

speaker+50 ohm

in case i decide to use a series resistor could i also choose a easy to find 8 OHM speaker with a proper resistor??

 

[Kral]

fuzzzy,
You could, but the required series resistor will drastically limit the power you can deliver to the speaker, due to current drive limitations of your device, which was designed to operate into a 50 Ohm load.
Regards,
Kral