# Great EE myths

manzana
These are some of my favorite myths I have encountered in my EE career...

1. NEVER mix Duracell and Eveready batteries in the same flashlight
2. Never leave your car battery on a cement floor, it will ground out and drain itself ( A metal shelf on concrete is OK)
3. Never use a wireless phone during an electrical storm
4. You are safe from lightning in a car because it isn't grounded
5. Cell phones use satellites to communicate (what are those big towers for?)
6. I need 100 ohm coax so I will just use 2 50 ohm pieces in series

MY FAVORITE:
7. For $20 you can by a rubber strip at the truck stop to ground your car and make it invisible to police radar. (Watch out for lightning though..) cnh1995 and davenn ## Answers and Replies zoobyshoe 2. Never leave your car battery on a cement floor, it will ground out and drain itself ( A metal shelf on concrete is OK) Someone posted a thread about this recently. The problematic claim was worded, "Never leave a car battery on a cement floor. It will ruin it." The last sentence is ambiguous, but is meant to warn that fumes from the battery will ruin the cement floor. But, because of the ambiguous wording, it's easy to suppose it means the cement floor will ruin the battery. Homework Helper Gold Member These are some of my favorite myths I have encountered in my EE career... 1. NEVER mix Duracell and Eveready batteries in the same flashlight 2. Never leave your car battery on a cement floor, it will ground out and drain itself ( A metal shelf on concrete is OK) 3. Never use a wireless phone during an electrical storm 4. You are safe from lightning in a car because it isn't grounded 5. Cell phones use satellites to communicate (what are those big towers for?) 6. I need 100 ohm coax so I will just use 2 50 ohm pieces in series MY FAVORITE: 7. For$20 you can by a rubber strip at the truck stop to ground your car and make it invisible to police radar. (Watch out for lightning though..)

Those are pretty good. I've heard many of them, and yes they are pretty silly. What's worse is barring cell phone usage at gas stations (petrol stations) citing safety reasons. That's just a load of hooey.

There might be a touch of truth to #1 though. When you change batteries, preferably you should change them together and use batteries of the same brand. The issue is that since the battery cells are in series, as is typically the case with a flashlight ("torch" for all you European yahoos people), as the battery depletes there is a real chance that the cell with the least amount of charge will find its polarity reversed. When this happens it will very likely corrode and may damage the flashlight (torch).

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Gold Member
4. You are safe from lightning in a car because it isn't grounded

there's a lot of truth in this one as well. BUT NOT because it isn't grounded, but because it is a reasonable Faraday cage

Dave

cnh1995
Gold Member
but because it is a reasonable Faraday cage
Poor Faraday, why are there some many people that want to catch him and lock him in?

davenn
Gold Member
hahaha

DennisN