# NEED HELP: AC or DC Circuit: Indicating light and latching relay on each leg/branch

#### HighVoltage!

Joined Apr 28, 2014
177
In need help (I am stuck) :

I am trying to design an AC or DC circuit in which indicates when any of the six legs/branches make contact with another (Obviously, there would have to be current limiting resistors in each leg because a SHORT is a "no-no"). There must be a minimum of 6 legs (Legs A, B, C, D, E, & F)...

Ex: If legs A, B, & C touch (the three legs short to each other), for each leg/branch, I would like an indicating light to illuminate only when contact is physically made with another leg(s). Additionally, I would like a relay for each respective leg to "latch" when contact is made with another leg, so that when contact is no longer made, we can see which legs made contact or were involved in a "short circuit". This same idea will apply if another combination were to occur such as A, C, D, & F etc.

#### crutschow

Joined Mar 14, 2008
33,365
Lots of questions:
• So you have complete choice over what voltage/signal is on each leg?
• Is there anything else connected to these legs?
• How fast do you need to detect that this has happened?
• What is the minimum contact time between any two wires?

#### HighVoltage!

Joined Apr 28, 2014
177
So you have complete choice over what voltage/signal is on each leg?
Is there anything else connected to these legs?
Thanks for the prompt response.

I am ok with (For safety reasons):
For AC up to 220VAC (AC we have less chance of capacitive charging vs DC)
For DC if can be done with an over the counter battery, would be great! (Ex: Car battery, 9V battery, lantern battery, etc..)

Nothing is connected to each leg, The only connections shall be leg-to-leg or multiple legs to each another.

#### Ya’akov

Joined Jan 27, 2019
8,553
In need help (I am stuck) :

I am trying to design an AC or DC circuit in which indicates when any of the six legs/branches make contact with another (Obviously, there would have to be current limiting resistors in each leg because a SHORT is a "no-no"). There must be a minimum of 6 legs (Legs A, B, C, D, E, & F)...

Ex: If legs A, B, & C touch (the three legs short to each other), for each leg/branch, I would like an indicating light to illuminate only when contact is physically made with another leg(s). Additionally, I would like a relay for each respective leg to "latch" when contact is made with another leg, so that when contact is no longer made, we can see which legs made contact or were involved in a "short circuit". This same idea will apply if another combination were to occur such as A, C, D, & F etc.
Given the odd and complicated description, it would be extremely helpful if you'd describe what problem this is a solution to.

#### HighVoltage!

Joined Apr 28, 2014
177
Given the odd and complicated description, it would be extremely helpful if you'd describe what problem this is a solution to.
This is a project given by my professor who does not like to being questioned . He said reasoning will be given/explained once its completed, which will be combined with Part 2 of project. "Things will come together".

#### Ya’akov

Joined Jan 27, 2019
8,553
This is a project given by my professor who does not like to being questioned . He said reasoning will be given/explained once its completed, which will be combined with Part 2 of project. "Things will come together".
That's a shame. If that professor was a colleague of ,mine, I'd tell him he was doing damage to his students by teaching them that is it possible to do good work without relevant information. If he was a potential client, and gave me this spec, I would find my schedule full.

Good luck with the class.

#### HighVoltage!

Joined Apr 28, 2014
177
That's a shame. If that professor was a colleague of ,mine, I'd tell him he was doing damage to his students by teaching them that is it possible to do good work without relevant information. If he was a potential client, and gave me this spec, I would find my schedule full.

Good luck with the class.