How to prevent Squirrels from chewing Christmas lights?

[The HalfBreed]

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They are 110V lights. See my post #37.

Even if the critter makes a 'short' between a part of the circuit with current limited by the full 50 LEDs in series, that's enough current to give it a severe/painful shock. Elsewhere in the line will result in a higher and higher current. So these 110V LED strings could provide a severe/painful shock, even though individual LEDs are ~ 3V each.

But as described in that post, making contact in that way is unlikely (bridging both the hot and neutral lines at once).

-ERD50

LED's work on 3-5VDC Max. I'm fairly sure there's a transformer somewhere in the circuit that reduces the voltage and possibly changes it to DC. (AC/DC Converter)....Who Knows. Either the lights are in series, or in groups of parallel circuits of 5-10 each.

Either way, my comment was meant as a joke. I've been an engineering technician for over 39 years and I'm pretty sure I have a handle on this.

 

[ERD50]

LED's work on 3-5VDC Max. I'm fairly sure there's a transformer somewhere in the circuit that reduces the voltage and possibly changes it to DC. (AC/DC Converter)....Who Knows. Either the lights are in series, or in groups of parallel circuits of 5-10 each.

Either way, my comment was meant as a joke. I've been an engineering technician for over 39 years and I'm pretty sure I have a handle on this.

OK, sorry that I missed the joke. I realized it was sort of a joke, in that it would be 'funny' to zap the critters with 110 Volts, but...

"Who Knows."? I do, and so does the internet, you can look it up:

you shouldn't even be 'fairly sure' that there is a step-down transformer, that's not typical at all for these sorts of holiday lights.

"Either the lights are in series". Bingo!

The typical LED strings are in series, typically in groups of 50. White LEDs have a typical Forward Voltage drop of ~ 3V (but start to illuminate at a somewhat lower voltage), so 3V x 50 in series is 150V. What we call 110V or 120V AC is an RMS value, the peak voltage of 120 V is ~ 170V. The strings typically have a series resistor so the LEDS aren't over-driven at that voltage.

On a 100 LED string, one group of 50 is on one polarity of the AC, the other group of 50 is on the opposite polarity. That's one of the reasons they flicker so badly (at least the typical cheap ones), each LED is on for only a portion of each half-wave, so a strong 60 Hz flicker from each 'bulb' (120 Hz including both polarities).

So yes, if a critter chews opens the circuit, they would be exposed to 120V RMS across that gap, current limited by the string of LEDs, or if they 'shorted' themselves between hot and neutral, they would be exposed to 120V RMS, current limiting would depend on how many LEDs are in the circuit at that point.

No joke

-ERD50

 

[Koolau]

OK, sorry that I missed the joke. I realized it was sort of a joke, in that it would be 'funny' to zap the critters with 110 Volts, but...

"Who Knows."? I do, and so does the internet, you can look it up:

you shouldn't even be 'fairly sure' that there is a step-down transformer, that's not typical at all for these sorts of holiday lights.

"Either the lights are in series". Bingo!

The typical LED strings are in series, typically in groups of 50. White LEDs have a typical Forward Voltage drop of ~ 3V (but start to illuminate at a somewhat lower voltage), so 3V x 50 in series is 150V. What we call 110V or 120V AC is an RMS value, the peak voltage of 120 V is ~ 170V. The strings typically have a series resistor so the LEDS aren't over-driven at that voltage.

On a 100 LED string, one group of 50 is on one polarity of the AC, the other group of 50 is on the opposite polarity. That's one of the reasons they flicker so badly (at least the typical cheap ones), each LED is on for only a portion of each half-wave, so a strong 60 Hz flicker from each 'bulb' (120 Hz including both polarities).

So yes, if a critter chews opens the circuit, they would be exposed to 120V RMS across that gap, current limited by the string of LEDs, or if they 'shorted' themselves between hot and neutral, they would be exposed to 120V RMS, current limiting would depend on how many LEDs are in the circuit at that point.

No joke

-ERD50

Okay, you lost me at 110 volts. I never could figure out AC.

 

[ERD50]

Okay, you lost me at 110 volts. I never could figure out AC.

It's easy (in this case), if you understand DC basics .

Imagine a battery with a dial you can turn from 0V to 170V. Hook it up to the string of 50 series LEDs, with a series current limiting resistor.

A) Turn the dial from 0V to 170V and back to zero.
B) Now reverse the leads, repeat the dial action from 0V to 170V and back to zero. .
C) go to A

Now practice so you can do it 60 times a second

-ERD50

 

[Koolau]

It's easy (in this case), if you understand DC basics .

Imagine a battery with a dial you can turn from 0V to 170V. Hook it up to the string of 50 series LEDs, with a series current limiting resistor.

A) Turn the dial from 0V to 170V and back to zero.
B) Now reverse the leads, repeat the dial action from 0V to 170V and back to zero. .
C) go to A

Now practice so you can do it 60 times a second

-ERD50

Thanks. That makes it all very clear. I guess. Or, maybe not.