Please explain human EM interference with my XMAS lights

In summary, the human body's electrical properties can sometimes cause strange reactions with devices like light bulbs, as seen in a malfunctioning electric candle that turned on and off when a hand was moved close to it. This could be due to a floating CMOS logic input, which has a high input impedance and can be affected by static charge. The candle does not have an on/off switch and it is unclear if the strange behavior still occurs with the bulb.
  • #1
stevenstritt
13
0
I am aware that the human body has electrical properties, But was baffled by what I witnessed Christmas Eve. I had a malfunctioning electric candle in the window. I picked it up to check the tightness of the bulb, and it immediately came on. I set it down and it went off. Three times this happened before I discovered that I did not even need to touch it, but merely move my hand close and it would light up. My question is how can so simple a device as a light bulb react this way, and why does this not happen all the time?
 
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  • #2
stevenstritt said:
I am aware that the human body has electrical properties, But was baffled by what I witnessed Christmas Eve. I had a malfunctioning electric candle in the window. I picked it up to check the tightness of the bulb, and it immediately came on. I set it down and it went off. Three times this happened before I discovered that I did not even need to touch it, but merely move my hand close and it would light up. My question is how can so simple a device as a light bulb react this way, and why does this not happen all the time?

Often with weird stuff like that, there is a floating CMOS logic input that is the cause. A floating CMOS logic gate input has very high input impedance, and static charge on your hand can generate enough of a field to push the gate input high and low. I've had this happen to me several times on prototype circuits where I wasn't paying attention and didn't tie off unused inputs.

How does this candle normally turn on and off? Does it have a button?
 
  • #3
There is no on/off switch
thanks
 
  • #4
stevenstritt said:
There is no on/off switch
thanks

Was the bulb incandescent or LED? Does it still exhibit this weird behavior?
 
  • #5
It was incandescent. It was not actually at my house so I don't know. There were actually 3 lights behaving this way, and 3 others that didn't
 

Related to Please explain human EM interference with my XMAS lights

1. How does human EM interference affect my XMAS lights?

Human EM interference can cause flickering, dimming, or complete failure of your XMAS lights. This is because our bodies naturally emit electromagnetic radiation, which can interfere with the electrical signals in your lights and disrupt their functioning.

2. Can I prevent human EM interference with my XMAS lights?

There are a few steps you can take to minimize the effects of human EM interference. One option is to use LED lights, which are less susceptible to interference. You can also try using different power outlets or using a surge protector to help filter out any interference.

3. Is human EM interference harmful to my XMAS lights?

In most cases, human EM interference does not cause any permanent damage to your XMAS lights. However, if the interference is strong enough, it could potentially damage the electrical components in your lights and shorten their lifespan.

4. Why do my XMAS lights only seem to be affected when I'm nearby?

As humans, we emit a stronger electromagnetic field when we are closer to a source of electricity. This means that the closer you are to your XMAS lights, the more likely it is that your body's EM radiation will interfere with them.

5. Can other electronic devices cause interference with my XMAS lights?

Yes, other electronic devices can also cause interference with your XMAS lights. This can include things like cell phones, Wi-Fi routers, and even nearby power lines. Keeping these devices away from your lights can help reduce interference.

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