Please confirm the information below before signing in. Already have an account? Sign In.
Please wait you will be redirected shortly.
We've sent an email with instructions to create a new password. Your existing password has not been changed.
Sorry, we could not verify that email address. Enter your email below, and we'll send you another email.
Check your email for a link to verify your email address.
Thank you for verifiying your email address.
Your password has been successfully updated.
We didn't recognize that password reset code. Enter your email below, and we'll send you another email.
We've sent you an email with instructions to create a new password. Your existing password has not been changed.
Return to Article
So, what does this rung do? |---[/]---------( )---| /K1 K1
|---[ A]----[/B]--+--( )----|
Originally, the potentials on the wires were positive with respect to earth (ground). This is called negative ground, since the negative side of the battery is grounded to earth. Telephone companies discovered that with positive voltage on the copper wires, copper wires experienced corrosion due to electrolysis. Operating in reverse, positive ground (negative voltage on the wires), the copper is protected from corrosion, a process called cathodic protection.