120vac indicators?

DaveGateway

what do you use to visually indicate 120vac?
ie voltage to a pump?
I can't seem to find 120vac LEDs
Thanks BP

Mark Hunt

Radio Shack


has 120v LED's. We used them on the last panel we did.

I drilled out holes in the Grundfos 15-58fc's and mountec them on the pumps. Looks neat when they're all lit up.

Hope this helps!


Mark H

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DaveGateway

120vac indicators?

Mark,
Do you have a part#?
I can't find them on the Radio Shack web-site.
I called their 1-800# & talked to 3 reps & no one can find them! Are they neon or LEDs?
Thanks

Mark Hunt

LED's


I don't have a part number on me, but I can get one for you later.

That ok?

Mark H

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Mark Hunt

Here they are!


http://www.radioshack.com/category.asp?catalog_name=CTLG&category_name=CTLG_011_006_001_000&Page=1



Mark H

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jim sokolovic

Assuming you want small ones...

I see part # 272-708 - 120 volt green lamp with lead wires and a 5/16" mounting hole, 2 pack for $2.59 (old catalog).

Better yet, they have horns you can attach to let everyone know "Here comes the heat"!

Robert O'Connor_7

Horns?

I gotta get some of them horns. Are they JUST horns, or can you get them to say "PAY THE BILL" too. Lights are a nice touch. Keep raising that bar! I do some building automation and I too bought the LED's from Radio Shack (good sorce).Robert O'Connor/NJ

DaveGateway

120vac indicators?

Mark,
thanks, but those LEDs are all DC.
They do have low cost 120vac neons in 3 colors.
BP

Mike T., Swampeast MO

LEDs are by definition DC devices. If they hook up to A/C you have to add other devices besides the normal current-limiting resistor.

Here's a link to simple schematics (110v A/C input)

110VAC LED Pilot Light Circuits

I guess someone makes these as a unit device, but I struck out. Sorry.

hr

Red or green?

The green come from Radio Shack 272-708A are in fact 120VAC maybe mislabeled in the catalog.

Johnstone Supply has red, only, in #G22-967

hot rod

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DaveGateway

120vac indicators?

Mike T.

I have found:
2v red LEDs (2-4k mcd intensity),
and diodes 1n914,
and resistors 1k.
I am not doing as well on .47ufd 200v caps (qty 100)?

To indicate 24vac ckts, would 5k resistors work with the 2v LEDs?
Thanks Bill Patrick

Mike T., Swampeast MO

Maybe this will help...

"The capacitor is used to drop the voltage and the resistor to limit the inrush current.

Since the capacitor passes the current in both directions, a small diode is connected in parallel with the LED to provide a path for the negative half cycle and to limit the reverse voltage across the LED. The resistor value was chosen to limit the worst case inrush current to about 150mA which will drop to less than 30mA in a millisec as the capacitor charges.

The 0.47uF capacitor has an impedance of 5600 Ohms at 60Hz so the LED current is about 20mA half wave, or 10mA average (for the 220V version the impedance of the 0.33uF capacitor is 9600 Ohms at 50Hz which gives you also a LED current of about 10mA average)."

Source: http://www.turbokeu.com/myprojects/acled.htm

Like most things, I'm self-taught when it comes to electronics. While I can produce reasonable circuits from schematics and identify many defective components, my knowledge of actually choosing appropriate components is extremely poor, so I just seek out schematics when someone else has done the "hard stuff". (Not that it's really that hard--I do understand the basics--but I design electronics so infrequently that I have to beat the books.)

From the above though it appears that you first select a capacitor to drop the A/C source to the appropriate level for the LED, and then size the resistor for the worst-case "inrush" (initial discharge peak) from the capacitor used.