How do you read an electrical schematic drawing?

Answer 1

schematic drawings explain electrical circuits. First you must know the basic requirments for any curcuit.

1. All circuits must do work. ( without a load the wiring becomes the load and it burns up. This is known as a short circuit.

2. All circuits must have an electrical path. From a voltage sourse to a load and back to the source.

3. There must be a way to control the electrical force. for example to turn it on and off.

When looking at schematics there are essential questions you should ask yourself. What is the intent of the circuit? How is it controlled? Where is the load? What is the load? Where is/are the controlling switches...etc? Is the contol voltage the same as the load voltage? What coil controls what contacts?

Schematics are often laid out as ladder diagrams. These show each simple circuit one at a time. IF they are now laid out a ladder diagrams many find it useful to redraw the schematics to put them in that form.

Schematics use symbols it represent different parts of the circuit. Often circles will denote a coil portion of a relay (or automatic switch) Often there will be a letter in the circle to identify the coil. That letter will also be assigned to sets of contacts that that coil operates. Contacts can be NO normally open or NC normally closed. Normally closed means that there is an electrical path across the contacts when the coil is not energized. Normally open means that the switch is off or there is no electrical path across the switch when the controlling coil is not energized.

This is a long subject and I will add to it from time to time. and any who know the subject are invited to add information to this answer as they wish.

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