I’m taking a class on burglar and hold-up alarms.
I get the basic theory behind the electrical connections, but I sometimes can’t figure out how to turn wiring diagrams into real-world circuits.
Does anyone have any suggestions as to how to study this stuff?
It seems like I have a mental block here.
PS- I would appreciate general study advice, but my deadling for learning this stuff is Thursday.
Perhaps you can specify what part you’re having trouble with?
Gladly, although I’m unsure how much I’ll be able to clarify.
I’ll have a diagram of a safe door.
I’ve got a shunt to allow the door to be opened without an alarm sounding so long as the door lock has been properly unbolted via the combination.
I’ve got a diagram sitting there, but when I have to tie down the 2 contacts from the door switch to the 2 contacts from the shunt on the lock to the terminal strips supplied in the safe. I can’t figure out how to line everything up in the real world so that the resistors found in my diagrams (even the ones I drew myself) are actually in the right order and tied to the right points on my alarm panel.
PS- I’m working on a mock-up. Real equipment, but no assets to protect. Don’t worry, I’m not ACTUALLY installing a needed alarm for someone who needs a working alarm to protect life/health/assets.
Is the alarm panel triggering off a normally open (NO) or normally closed (NC) circuit?
You mention resistors - is the panel looking for a logic pull-up or pull-down instead?
When you say “line everything up”, do you mean you’re not sure what each symbol represents, or you can’t find the component represented, or you can’t figure which wire goes to which connection?
Hmmm.
You’re getting into specifics, which isn’t my goal here, but if this is going somewhere helpful I’m all for it.
It’s not this single circuit that’s kicking my butt, it seems to be any circuit with more than 5 connections. I can read them, but turning them into wires just kills me.
The loop on the panel watching the door switch & shunt is normally closed and supervised with a resistor, if I understand my terms.
Good questions.
I know what my symbols represent; this class doesn’t use many symbols, and mostly labels my decies.
I can generally find the represented components and have a good grasp on what my devices look like.
I can’t figure out which wire goes to which connection comes closest to describing it.
I’ve got a common that ties to a resistor and another two commons, one on another ‘device’ and another on the loop on the alarm panel.
What exactly do I punch down onto the point for this common?
I’m thinking the answer is to crimp 4 wires into the common and then run these wires into the various devices. I’m not sure, though.
I don’t quite get why I’m getting this confused by these things, which I suspect really aren’t all that hard.
Well, if the common is the same point electrically it doesn’t matter (in practical terms here) what device is connect physically to which point of the common.
Yes, you could crimp 4 wires to the end of the common and run them to the points in question (like a pitchfork), or you could just daisy chain the connection from the same common point on all of the devices (like a bunch of “VVVVVVVs.” Transferring schematics into reality can take a bit of getting used to. Keep at it and you’ll reach a “eureka” point in no time. The wire doesn’t care how it’s connected really, so whatever physical connection that will still meet the schematic representation is acceptable (at least for the purpose of alarm systems, unless your wire is like 1 Km long or something).
When I teach basic electrical with new technicians, I use a power supply some light bulbs, jumper wires and alike. I make them wire up stupidly simple circuits using those items. I have them take measurements on those circuits.
By lunch time I have them reading wiring diagrams.
In your case, it might help to get some jumper wires from Radio Shack and some of the components and try it out.
Also try wiring up something and then drawing a diagram of what you just wired. I have found that doing this many times clears up confusion in the students mind about a circuit.
Good luck
R
I got distracted before I left work, but did Leaffan and Rick give you enough info to get you pointed in the right direction?
Similar to what Leaffan said, if you think of, for example, the frame of a car as one big wire, that may help with the understanding of how a common/ground works. Let us know if you have any other questions!