120 volt LED design

[[email protected]]

Is it possible that I can add an LED in series with a 120 Volt AC
circuit, this will light up to indicate that I have power when a load
is connected. This LED will have to handle 15 amp load

 

[Michael A. Terrell]

Is it possible that I can add an LED in series with a 120 Volt AC
circuit, this will light up to indicate that I have power when a load
is connected. This LED will have to handle 15 amp load

You got no brain. What planet are you from? Look up LED spec, see the current and do a little math will you? Don't expect people to put foods in your mounth. This is an easy job. Don't ask!



--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[sycochkn]

Is it possible that I can add an LED in series with a 120 Volt AC
circuit, this will light up to indicate that I have power when a load
is connected. This LED will have to handle 15 amp load

1500 leds in parallel.

Bob

 

[John Popelish]

Is it possible that I can add an LED in series with a 120 Volt AC
circuit, this will light up to indicate that I have power when a load
is connected. This LED will have to handle 15 amp load

Have you heard of current transformers? That is what I
would use to connect a pair of LEDS in series with an AC load.

Perhaps something like this one:
ttp://www.netsuite.com/core/media/media.nl?id=3354&c=ACCT126831&h=467c29543fa58c37926a&_xt=.pdf

 

[BobW]

You got no brain. What planet are you from? Look up LED spec, see the
current and do a little math will you? Don't expect people to put foods
in your mounth. This is an easy job. Don't ask!

Michael A. Terrell

I don't think you understand what the OP is asking for.

To me, it seems like he wants something that will light up when when a light
load is connected to his "led box", and will also light and not blow up when
a 15A load is connected to it, too.

This is not such a trivial design.

Bob

 

[[email protected]]

I don't think you understand what the OP is asking for.

To me, it seems like he wants something that will light up when when a light
load is connected to his "led box", and will also light and not blow up when
a 15A load is connected to it, too.

This is not such a trivial design.

Bob

U can use a capacitor as a resistor for ac ccts. Cheaper than xfmr as
long as u keep it safe.

 

[sycochkn]

I don't think you understand what the OP is asking for.

To me, it seems like he wants something that will light up when when a
light load is connected to his "led box", and will also light and not blow
up when a 15A load is connected to it, too.

This is not such a trivial design.

Bob

Johns current transformer idea sounds like a good one a little amplification
with an op amp and you have lots of range. or a hall sensor. current probe
etc.



Bob

 

[[email protected]]

I don't think you understand what the OP is asking for.

To me, it seems like he wants something that will light up when when a light
load is connected to his "led box", and will also light and not blow up when
a 15A load is connected to it, too.

This is not such a trivial design.

Bob

thanks for the response, I do believe I will have to incorporate a CT
(current transducer) I know that LEDs can't handle current and will
now need advise on hooking up a very small CT to light up an LED when
current is detected, on a 120 volt AC line. thanks for all
responses. (And yes I do have a brain,)

 

[[email protected]]

Is it possible that I can add an LED in series with a 120 Volt AC
circuit,  this will light up to indicate that I have power when a load
is connected.  This LED will have to handle 15 amp load

A cheap way to sense current is to wrap a few turns of one wire around
a read relay. mmm good for "bulb out" sensor on a car but not sure
about Ac?
Then use capacative reactance for Led supply.
Mike

 

[Michael A. Terrell]

I don't think you understand what the OP is asking for.

To me, it seems like he wants something that will light up when when a light
load is connected to his "led box", and will also light and not blow up when
a 15A load is connected to it, too.

This is not such a trivial design.

Bob

You replied to a forged post by jackthehammer. I have never had an
account with aioe.org.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Spehro Pefhany]

On Sun, 24 Feb 2008 20:37:43 -0800 (PST), the renowned

Is it possible that I can add an LED in series with a 120 Volt AC
circuit, this will light up to indicate that I have power when a load
is connected. This LED will have to handle 15 amp load

No, that's not realistically possible unless you want to spend
hundreds of dollars minimum and light up the room.

A small metal core toroidal current transformer (run a wire through
the core for the primary) can be used.



Best regards,
Spehro Pefhany

 

[petrus bitbyter]

Is it possible that I can add an LED in series with a 120 Volt AC
circuit, this will light up to indicate that I have power when a load
is connected. This LED will have to handle 15 amp load

120V~
| |
| |
| |
| | +-----+
| o | |
| | | |
| +-----+ | .-.
| | |5V~ 120V~ | | |2k2
| .-. +---. ,------+ .-----. | | |
| | | )|( +-| ~/ |-+ '-'
| | |.02R/5W )|( +---| / = |---+ |
| '-' +---' '----+ '-----' | |
| | | 100mA | V LED
| +-----+ | -
| | | |
| o +---+
| |
| |
| |
created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de

For measuring or signaling current the best thing you can use is a current
transformer. But this tend to be expensive things that are not always
available.

If you only want to signal the current in 10-15A range, the circuit above
will do.
Be sure to make proper connections between the 0.02R/5W resistor and the
main line. A bad connection will become hot and fry itself. The resistor
will become hot as well so provide enough ventilation.
Connect the transformer directly to the resistor (so not to the line).
The transformer can be a ordinary 100mA type. Even a 50mA type may do though
it can become a little bit too warm. Mention its orientation.
Use a low current type for the LED. A 2mA type will do.

As the circuit is directly connected to the mains, use proper insulation.
120V~ does not always kill but you don't want to be the exception... I guess


petrus bitbyter

 

[Don Klipstein]

No, that's not realistically possible unless you want to spend
hundreds of dollars minimum and light up the room.

A small metal core toroidal current transformer (run a wire through
the core for the primary) can be used.

I would put two big diodes in reverse parallel, and that goes in series
with the load. Then use a transformer to step up the voltage across the
diodes to a level that will light an LED. This will have the LED
brightness only varying a little with load current, as long as the load
current is enough to make the transformer light an LED.

- Don Klipstein ([email protected])

 

[Bill Bowden]

  I would put two big diodes in reverse parallel, and that goes in series
with the load.  Then use a transformer to step up the voltage across the
diodes to a level that will light an LED.  This will have the LED
brightness only varying a little with load current, as long as the load
current is enough to make the transformer light an LED.

 - Don Klipstein ([email protected])

Problem is, you might get a current spike that blows the LED when the
thing is switched on or off. I tried to use an LED in a 1KW space
heater as an indicator light, and just used a diode and resistor
across the low voltage fan which was in series with the heating
element. It worked for a few hours and then blew the LED. So I
replaced it and tried again with same result. I finally just put the
LED and large power resistor in parallel with the entire load and
never had any more problems. The extra heat from the power resistor
just helped heat up the room.

-Bill

 

[Don Klipstein]

Problem is, you might get a current spike that blows the LED when the
thing is switched on or off. I tried to use an LED in a 1KW space
heater as an indicator light, and just used a diode and resistor
across the low voltage fan which was in series with the heating
element. It worked for a few hours and then blew the LED. So I
replaced it and tried again with same result. I finally just put the
LED and large power resistor in parallel with the entire load and
never had any more problems. The extra heat from the power resistor
just helped heat up the room.

OK, I would either add a bridge rectifier or use two inverse-parallel
LEDs. A suitable dropping resistor is needed of course.

With the transformer primary's voltage limited to a diode drop, I doubt
anything bad will happen to the LEDs unless those primary diodes fail
open or the power line is hit by lightning. (Put a fuse in series with
the transformer primary in case those diodes open.)

- Don Klipstein ([email protected])

 

[Bill Bowden]

In <890f82[email protected]>,








  OK, I would either add a bridge rectifier or use two inverse-parallel
LEDs.  A suitable dropping resistor is needed of course.

  With the transformer primary's voltage limited to a diode drop, I doubt
anything bad will happen to the LEDs unless those primary diodes fail
open or the power line is hit by lightning.  (Put a fuse in series with
the transformer primary in case those diodes open.)

 - Don Klipstein ([email protected])- Hide quoted text -

- Show quoted text -

Yes, it will probably work if the 15 amp power diodes are fast enough
to respond to short current spikes. I think my problem was the
inductance of the fan motor bumped up the voltage considerably when
power was switched off.

-Bill

 

[JosephKK]

Is it possible that I can add an LED in series with a 120 Volt AC
circuit, this will light up to indicate that I have power when a load
is connected. This LED will have to handle 15 amp load

Just buy a 120v LED indicator and wire it in parallel with the load.
Then load current from 0 to blows the breaker does not matter.