I am re-capping an Emerson 543 and it has a .0005mf capacitor rated at 600 volts. Can I use .001 mf at 630 volts? I am not sure how much tolerance is acceptable. I have not run into a paper capacitor this small before. Ron

Ron,

You could use a couple of .001MFD caps in series, that will give you the .0005MFD. Or you could use a 500PF mica or ceramic cap. They don't necessarily need to be rated at 630 volts as the radio is an AC/DC radio with at the most up to 120 volts or so B+. The cap is located between the plate and B- of the second detector and the voltage there is most likely some value less than 100 volts.

Radiodoc
**********

:I am re-capping an Emerson 543 and it has a .0005mf capacitor rated at 600 volts. Can I use .001 mf at 630 volts? I am not sure how much tolerance is acceptable. I have not run into a paper capacitor this small before. Ron

Radiodoc,

Thanks for helping out, I do have a 500 Pf at 500 volts, but I am rather new at this and have read to never use a lower voltage only lower.

Ron

:Ron,
:
:You could use a couple of .001MFD caps in series, that will give you the .0005MFD. Or you could use a 500PF mica or ceramic cap. They don't necessarily need to be rated at 630 volts as the radio is an AC/DC radio with at the most up to 120 volts or so B+. The cap is located between the plate and B- of the second detector and the voltage there is most likely some value less than 100 volts.
:
:Radiodoc
:**********
:
::I am re-capping an Emerson 543 and it has a .0005mf capacitor rated at 600 volts. Can I use .001 mf at 630 volts? I am not sure how much tolerance is acceptable. I have not run into a paper capacitor this small before. Ron

Hi Ron

Are you talking about C12?

http://www.nostalgiaair.org/PagesByModel/648/M0004648.pdf

You can use a larger cap,.001 in place of .0005 mf. Why not use 470 pf mica cap if you have one? This cap removes IF frequency from the audio. There will be a slight loss of high frequency response using a larger value.

Norm

:I am re-capping an Emerson 543 and it has a .0005mf capacitor rated at 600 volts. Can I use .001 mf at 630 volts? I am not sure how much tolerance is acceptable. I have not run into a paper capacitor this small before. Ron

Norm,

The radio I am working on uses the larger tubes so the schematic is on page 4, chassis 12052 and it is C10. Another gentleman suggested I use a 500 pf ceramic, which I have, but it is only rated at 500 volts. I am pretty new at this and I had read to always go over on voltage not under.

Thanks,
Ron

:Hi Ron
:
: Are you talking about C12?
:
:http://www.nostalgiaair.org/PagesByModel/648/M0004648.pdf
:
: You can use a larger cap,.001 in place of .0005 mf. Why not use 470 pf mica cap if you have one? This cap removes IF frequency from the audio. There will be a slight loss of high frequency response using a larger value.
:
:Norm
:
::I am re-capping an Emerson 543 and it has a .0005mf capacitor rated at 600 volts. Can I use .001 mf at 630 volts? I am not sure how much tolerance is acceptable. I have not run into a paper capacitor this small before. Ron

You don't really need anything rated higher than 250 volts in an AC/DC radio, though 500 or 600 is just fine. Using capacitors rated for 500 or 600 WV helps protect them against voltage spikes.

As Norm and others said, changing the value significantly will affect the audio, particularily in the higher register, which may or may not be to your liking. If you want the radio to perform like it did from the factory, you should stick to original values whenever possible (470 pF is acceptable for 500 pF, or .00047 or .0005 MFD, respectively....they are the same thing).

For typical super heterodyne radios, capacitors across a signal source will attenuate the higher frequencies (either radio or audio, depending on the circuit and the capacitor). A capacitor in parallel with a coil will cause the coil to resonate at a certain frequency. Changing the value of the capacitor will change that resonant frequency (this even holds true for the output transformer, which is why a tone muting capacitor not only reduces the highs, but also accentuates the middle tones). Capacitors in the AVC circuit affect its response frequency (which should normally be around 1/10 of a second). Capacitors in series with any signal source will limit lower frequencies if the capacitor is small enough. Capacitors in the power circuit (large value) absorb and fill in pulsations. If the capacitors are not large enough, they will not be able to respond well enough to the low 60 or 120 cycle pulsations.

There are many other applications for capacitors. Just remember that when a capacitor is across a signal source, it absorbs some of that signal. When it is in series with a signal source, it passes at least some of that signal through. The larger the capacitor value, the more the capacitor will pass low frequencies. Most capacitors will respond well to higher frequencies, and will taper off as frequencies get lower (what values work well for what frequencies depends on the frequencies in use, as well as circuit impedances, and other factors). Knowing this helps you know what changing a capacitor value will do to the circuit.

Thomas

Wow! that was extremely helpful!! I think I will print it off and read it a few time - sometimes it takes a while to penetrate my thick skull.

Thank you very much,
Ron

:You don't really need anything rated higher than 250 volts in an AC/DC radio, though 500 or 600 is just fine. Using capacitors rated for 500 or 600 WV helps protect them against voltage spikes.
:
:As Norm and others said, changing the value significantly will affect the audio, particularily in the higher register, which may or may not be to your liking. If you want the radio to perform like it did from the factory, you should stick to original values whenever possible (470 pF is acceptable for 500 pF, or .00047 or .0005 MFD, respectively....they are the same thing).
:
:For typical super heterodyne radios, capacitors across a signal source will attenuate the higher frequencies (either radio or audio, depending on the circuit and the capacitor). A capacitor in parallel with a coil will cause the coil to resonate at a certain frequency. Changing the value of the capacitor will change that resonant frequency (this even holds true for the output transformer, which is why a tone muting capacitor not only reduces the highs, but also accentuates the middle tones). Capacitors in the AVC circuit affect its response frequency (which should normally be around 1/10 of a second). Capacitors in series with any signal source will limit lower frequencies if the capacitor is small enough. Capacitors in the power circuit (large value) absorb and fill in pulsations. If the capacitors are not large enough, they will not be able to respond well enough to the low 60 or 120 cycle pulsations.
:
:There are many other applications for capacitors. Just remember that when a capacitor is across a signal source, it absorbs some of that signal. When it is in series with a signal source, it passes at least some of that signal through. The larger the capacitor value, the more the capacitor will pass low frequencies. Most capacitors will respond well to higher frequencies, and will taper off as frequencies get lower (what values work well for what frequencies depends on the frequencies in use, as well as circuit impedances, and other factors). Knowing this helps you know what changing a capacitor value will do to the circuit.
:
:Thomas

Actually, capacitors hold charges. The capacitance has to do with the electrical size of the capacitor. For me to say that a capacitor absorbs a signal or voltage fluctuation is kind of wrong. What it does is it fills up with current flowing one way, and then releases its fill when the current starts going the other way. In the case of pulsating DC, such as that found in your power circuit, the capacitors charge up whenever the power supply has voltage, and then release their charge whenever the power supply doesn't have voltage (this happens either 60 or 120 times a second, depending on the rectifier circuit and the alternating current frequency being fed to the supply). In either case, the capacitor absorbs and then releases charges, which tends to nulify voltage variation. If the capacitor across the signal source is large enough to completely absorb and fill in voltage variations in the circuit, it will tend to nullify variations in voltage at that particular frequency and higher. As the frequency gets lower (should the frequency vary), the capacitor will not be able to completely absorb and/or fill in fluctuations. If a voltage is one way or another for a longer period of time (lower frequency), such a voltage will occupy a greater electrical space. The capacitor will be full before the complete voltage period is complete, and the remaining part of that votlage will not be absorbed, or, when the capacitor is releasing for an opposite polarity, filled in. This is a lot easier to explain with graph paper.

When a capacitor is in series with a circuit, and voltage is being fed through it, you can see how it would not pass lower frequencies as well as higher ones because a capacitor of a certain size can only charge up so much. Once filled, no more can enter into or out of it. Current never flows through a capacitor, but when a capacitor is charging or discharging, it appears as though current is flowing through it, because current flows in the rest of the circuit as the capacitor charges or discharges. If a really low frequency is expected to 'pass' through a capacitor, but the capacitor charges up before each part of the wave is complete, the low frequency will not 'pass through' the capacitor as effectively as a higher frequency.

Also, impedance, as I said before, affects frequency response. Lower impedances will discharge and charge capacitors more rapidly than higher ones, which will make the capacitors less effective in the circuit. Lowering the impedance in many cases has an effect similar to decreasing the capacitance. Low frequency response (whatever that may be...depending on the circuitry) will diminish. A capacitor that is feeding a signal into a circuit will be loaded more heavily, and so what the capacitor is and is not efficient at passing will be accentuated more-so.

All of this is rather vague, but should get your foot in the door. Thorough reading and analysis of many different views on the subject can be a real help.

T.

:Actually, capacitors hold charges. The capacitance has to do with the electrical size of the capacitor. For me to say that a capacitor absorbs a signal or voltage fluctuation is kind of wrong. What it does is it fills up with current flowing one way, and then releases its fill when the current starts going the other way. In the case of pulsating DC, such as that found in your power circuit, the capacitors charge up whenever the power supply has voltage, and then release their charge whenever the power supply doesn't have voltage (this happens either 60 or 120 times a second, depending on the rectifier circuit and the alternating current frequency being fed to the supply). In either case, the capacitor absorbs and then releases charges, which tends to nulify voltage variation. If the capacitor across the signal source is large enough to completely absorb and fill in voltage variations in the circuit, it will tend to nullify variations in voltage at that particular frequency and higher. As the frequency gets lower (should the frequency vary), the capacitor will not be able to completely absorb and/or fill in fluctuations. If a voltage is one way or another for a longer period of time (lower frequency), such a voltage will occupy a greater electrical space. The capacitor will be full before the complete voltage period is complete, and the remaining part of that votlage will not be absorbed, or, when the capacitor is releasing for an opposite polarity, filled in. This is a lot easier to explain with graph paper.
:
:When a capacitor is in series with a circuit, and voltage is being fed through it, you can see how it would not pass lower frequencies as well as higher ones because a capacitor of a certain size can only charge up so much. Once filled, no more can enter into or out of it. Current never flows through a capacitor, but when a capacitor is charging or discharging, it appears as though current is flowing through it, because current flows in the rest of the circuit as the capacitor charges or discharges. If a really low frequency is expected to 'pass' through a capacitor, but the capacitor charges up before each part of the wave is complete, the low frequency will not 'pass through' the capacitor as effectively as a higher frequency.
:
:Also, impedance, as I said before, affects frequency response. Lower impedances will discharge and charge capacitors more rapidly than higher ones, which will make the capacitors less effective in the circuit. Lowering the impedance in many cases has an effect similar to decreasing the capacitance. Low frequency response (whatever that may be...depending on the circuitry) will diminish. A capacitor that is feeding a signal into a circuit will be loaded more heavily, and so what the capacitor is and is not efficient at passing will be accentuated more-so.
:
:All of this is rather vague, but should get your foot in the door. Thorough reading and analysis of many different views on the subject can be a real help.
:
:T.

::Actually, capacitors hold charges. The capacitance has to do with the electrical size of the capacitor. For me to say that a capacitor absorbs a signal or voltage fluctuation is kind of wrong. What it does is it fills up with current flowing one way, and then releases its fill when the current starts going the other way. In the case of pulsating DC, such as that found in your power circuit, the capacitors charge up whenever the power supply has voltage, and then release their charge whenever the power supply doesn't have voltage (this happens either 60 or 120 times a second, depending on the rectifier circuit and the alternating current frequency being fed to the supply). In either case, the capacitor absorbs and then releases charges, which tends to nulify voltage variation. If the capacitor across the signal source is large enough to completely absorb and fill in voltage variations in the circuit, it will tend to nullify variations in voltage at that particular frequency and higher. As the frequency gets lower (should the frequency vary), the capacitor will not be able to completely absorb and/or fill in fluctuations. If a voltage is one way or another for a longer period of time (lower frequency), such a voltage will occupy a greater electrical space. The capacitor will be full before the complete voltage period is complete, and the remaining part of that votlage will not be absorbed, or, when the capacitor is releasing for an opposite polarity, filled in. This is a lot easier to explain with graph paper.
::
::When a capacitor is in series with a circuit, and voltage is being fed through it, you can see how it would not pass lower frequencies as well as higher ones because a capacitor of a certain size can only charge up so much. Once filled, no more can enter into or out of it. Current never flows through a capacitor, but when a capacitor is charging or discharging, it appears as though current is flowing through it, because current flows in the rest of the circuit as the capacitor charges or discharges. If a really low frequency is expected to 'pass' through a capacitor, but the capacitor charges up before each part of the wave is complete, the low frequency will not 'pass through' the capacitor as effectively as a higher frequency.
::
::Also, impedance, as I said before, affects frequency response. Lower impedances will discharge and charge capacitors more rapidly than higher ones, which will make the capacitors less effective in the circuit. Lowering the impedance in many cases has an effect similar to decreasing the capacitance. Low frequency response (whatever that may be...depending on the circuitry) will diminish. A capacitor that is feeding a signal into a circuit will be loaded more heavily, and so what the capacitor is and is not efficient at passing will be accentuated more-so.
::
::All of this is rather vague, but should get your foot in the door. Thorough reading and analysis of many different views on the subject can be a real help.

RCWade
If you can, get a copy of the ARRL hand book, any year, they cover the basics very well with a minimum of math. This should be in every one's library, it's your basic book of electronics
::
::T.

:::Actually, capacitors hold charges. The capacitance has to do with the electrical size of the capacitor. For me to say that a capacitor absorbs a signal or voltage fluctuation is kind of wrong. What it does is it fills up with current flowing one way, and then releases its fill when the current starts going the other way. In the case of pulsating DC, such as that found in your power circuit, the capacitors charge up whenever the power supply has voltage, and then release their charge whenever the power supply doesn't have voltage (this happens either 60 or 120 times a second, depending on the rectifier circuit and the alternating current frequency being fed to the supply). In either case, the capacitor absorbs and then releases charges, which tends to nulify voltage variation. If the capacitor across the signal source is large enough to completely absorb and fill in voltage variations in the circuit, it will tend to nullify variations in voltage at that particular frequency and higher. As the frequency gets lower (should the frequency vary), the capacitor will not be able to completely absorb and/or fill in fluctuations. If a voltage is one way or another for a longer period of time (lower frequency), such a voltage will occupy a greater electrical space. The capacitor will be full before the complete voltage period is complete, and the remaining part of that votlage will not be absorbed, or, when the capacitor is releasing for an opposite polarity, filled in. This is a lot easier to explain with graph paper.
:::
:::When a capacitor is in series with a circuit, and voltage is being fed through it, you can see how it would not pass lower frequencies as well as higher ones because a capacitor of a certain size can only charge up so much. Once filled, no more can enter into or out of it. Current never flows through a capacitor, but when a capacitor is charging or discharging, it appears as though current is flowing through it, because current flows in the rest of the circuit as the capacitor charges or discharges. If a really low frequency is expected to 'pass' through a capacitor, but the capacitor charges up before each part of the wave is complete, the low frequency will not 'pass through' the capacitor as effectively as a higher frequency.
:::
:::Also, impedance, as I said before, affects frequency response. Lower impedances will discharge and charge capacitors more rapidly than higher ones, which will make the capacitors less effective in the circuit. Lowering the impedance in many cases has an effect similar to decreasing the capacitance. Low frequency response (whatever that may be...depending on the circuitry) will diminish. A capacitor that is feeding a signal into a circuit will be loaded more heavily, and so what the capacitor is and is not efficient at passing will be accentuated more-so.
:::
:::All of this is rather vague, but should get your foot in the door. Thorough reading and analysis of many different views on the subject can be a real help.
:
:RCWade
:If you can, get a copy of the ARRL hand book, any year, they cover the basics very well with a minimum of math. This should be in every one's library, it's your basic book of electronics
:::
:::T.

Gentleman,

Thanks for the lesson and the suggestion for the book, I will pick it up. Everyone on this forum is so helpful - I really appreciate it.

Ron