AC/DC chassis radio in car with power inverter

7/30/2008 10:56:40 AMDave Froehlich

Hello All,
Is there any way to get rid of the line interference caused by the square wave, so that an AC/DC radio will operate with a power inverter? If so what sort of wave shaper or "line-conditioner" do I need? Or is there a way I can make a DC-DC converter ('12v' (actually 13.8 v) to 110 vdc) that will work? I know there's a way to make a voltage doubler or voltage tripler. Maybe a combination of diodes and capacitors will get me a 9x increase with no AC involved.

Thanks,

Dave

7/30/2008 11:20:49 AMNorm Leal

Dave

Might try a line filter which has toroids and caps inside. It will reduce line noise but may not completely eliminate it.

Voltage multipliers, with diodes and caps, only work on AC. You can multiple AC voltage to just about any value but not DC.

Norm

:Hello All,
: Is there any way to get rid of the line interference caused by the square wave, so that an AC/DC radio will operate with a power inverter? If so what sort of wave shaper or "line-conditioner" do I need? Or is there a way I can make a DC-DC converter ('12v' (actually 13.8 v) to 110 vdc) that will work? I know there's a way to make a voltage doubler or voltage tripler. Maybe a combination of diodes and capacitors will get me a 9x increase with no AC involved.
:
:
:Thanks,
:
:Dave

7/30/2008 12:52:56 PMDave Froehlich

Norm,
What would the circuit look like?

Thanks.

Dave
:Dave
:
: Might try a line filter which has toroids and caps inside. It will reduce line noise but may not completely eliminate it.
:
: Voltage multipliers, with diodes and caps, only work on AC. You can multiple AC voltage to just about any value but not DC.
:
:Norm
:
::Hello All,
:: Is there any way to get rid of the line interference caused by the square wave, so that an AC/DC radio will operate with a power inverter? If so what sort of wave shaper or "line-conditioner" do I need? Or is there a way I can make a DC-DC converter ('12v' (actually 13.8 v) to 110 vdc) that will work? I know there's a way to make a voltage doubler or voltage tripler. Maybe a combination of diodes and capacitors will get me a 9x increase with no AC involved.
::
::
::Thanks,
::
::Dave

7/30/2008 4:04:30 PMCarl T

Norm,
Would the filter used in computer monitors work in this application? It wouldn't be hard to come up with one out of an older crt monitor.
Carl T

:Dave
:
: Might try a line filter which has toroids and caps inside. It will reduce line noise but may not completely eliminate it.
:
: Voltage multipliers, with diodes and caps, only work on AC. You can multiple AC voltage to just about any value but not DC.
:
:Norm
:
::Hello All,
:: Is there any way to get rid of the line interference caused by the square wave, so that an AC/DC radio will operate with a power inverter? If so what sort of wave shaper or "line-conditioner" do I need? Or is there a way I can make a DC-DC converter ('12v' (actually 13.8 v) to 110 vdc) that will work? I know there's a way to make a voltage doubler or voltage tripler. Maybe a combination of diodes and capacitors will get me a 9x increase with no AC involved.
::
::
::Thanks,
::
::Dave

7/30/2008 7:57:10 PMNorm Leal

Good suggestion Carl. The filter would have a toroid coil in series with each side of the line. In addition caps across the line, both sides of the coils. If you have three wires there will be caps from the line to ground.

Norm

:Norm,
:Would the filter used in computer monitors work in this application? It wouldn't be hard to come up with one out of an older crt monitor.
:Carl T
:
::Dave
::
:: Might try a line filter which has toroids and caps inside. It will reduce line noise but may not completely eliminate it.
::
:: Voltage multipliers, with diodes and caps, only work on AC. You can multiple AC voltage to just about any value but not DC.
::
::Norm
::
:::Hello All,
::: Is there any way to get rid of the line interference caused by the square wave, so that an AC/DC radio will operate with a power inverter? If so what sort of wave shaper or "line-conditioner" do I need? Or is there a way I can make a DC-DC converter ('12v' (actually 13.8 v) to 110 vdc) that will work? I know there's a way to make a voltage doubler or voltage tripler. Maybe a combination of diodes and capacitors will get me a 9x increase with no AC involved.
:::
:::
:::Thanks,
:::
:::Dave

7/30/2008 7:57:59 PMDoug Criner

Actually, there is a "bucket-brigade" ckt that can be used to boost a DC voltage. Caps are charged, and then switched in and out. Not very practical though.

Using a square-wave input to an AC/DC radio is going to be a challenging filtration problem. A square wave has harmonics up the wazoo.
Doug

7/31/2008 3:52:02 PMDave Froehlich

Doug,
I know about the square-wave harmonics. How do I get rid of them? How do I condition the line? All I need is about 110 volts DC for an AC/DC set. Isn't there any kind of RLC circuit I can use, along with some rectifier diodes? The line conditioner would be a power supply that converts the 120 volts 60 Cycle square-wave to 110V DC. Would this be very expensive?

Thanks,

Dave
:Actually, there is a "bucket-brigade" ckt that can be used to boost a DC voltage. Caps are charged, and then switched in and out. Not very practical though.
:
:Using a square-wave input to an AC/DC radio is going to be a challenging filtration problem. A square wave has harmonics up the wazoo.
:Doug
:
::Dave
::
:: Might try a line filter which has toroids and caps inside. It will reduce line noise but may not completely eliminate it.
::
:: Voltage multipliers, with diodes and caps, only work on AC. You can multiple AC voltage to just about any value but not DC.
::
::Norm
::
:

7/31/2008 4:45:08 PMDoug Criner

Dave: I would just use a "pure sine wave" inverter. They are often used on boats and in RVs for running TVs, etc. You can do a Google search. They will convert 12-VDC to 120-VAC, via a cigarette plug.

(Although, they are called "pure sine wave," their waveforms are synthesized using digital technology, such as PWM. But it should avoid most of your problems.)

Even though radios were commonly classified as AC/DC, most were never run on DC. A DC source, say 110-120V, won't provide the correct voltage to both the filaments and to the plates. When an AC source is used, SQRT(2) comes into play - the peak voltage feeding the rectifier is 1.4 times the nominal RMS AC voltage. But, the radio will work, after a fashion.

I think we are wondering what the purpose of this project is? Seems like an unusual application to use an AC/DC radio in a car.
Doug

:Doug,
: I know about the square-wave harmonics. How do I get rid of them? How do I condition the line? All I need is about 110 volts DC for an AC/DC set. Isn't there any kind of RLC circuit I can use, along with some rectifier diodes? The line conditioner would be a power supply that converts the 120 volts 60 Cycle square-wave to 110V DC. Would this be very expensive?
:
:
:Thanks,
:
:Dave