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Pictorial Circuit Diagrams
42 questions
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Question 1 of 42
Sketch connecting wires such that the relay will energize when the normally-open (NO) pushbutton switch is pressed. Be sure to wire the relay in such a way that voltage will appear in the polarities shown by the (+) and (-) marks:
Reveal answerBear in mind that this is not the only possible circuit solution:
Challenge yourself by designing a different circuit to meet the same criteria!
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Use this wiring diagram to translate between the relay terminals and screws on the socket base.
Notes:This is called ‘power side switching’ because the switching device is connected between the load and the power supply (+) terminal.
Try to re-wire for ‘ground side switching’ - Read more here! -
Question 2 of 42
Sketch connecting wires such that the relay will energize when the normally-open (NO) pushbutton switch is pressed. Be sure to wire the relay in such a way that current (conventional flow) follows the directions indicated by the arrows:
Reveal answerBear in mind that this is not the only possible circuit solution:
Challenge yourself by designing a different circuit to meet the same criteria!
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Use this wiring diagram to translate between the relay terminals and screws on the socket base.
Note that this relay is rotated from the previous question.
Notes:This is called ‘ground side switching’ because the switching device is connected between the load and the power supply (-) terminal.
Try to re-wire for ‘power side switching’ - Read more here! -
Question 3 of 42
Sketch connecting wires such that the relay will energize and turn on the lamp when the normally-open (NO) pushbutton switch is pressed. Use the following schematic diagram as a guide:
Note how the relay coil and lamp are separate (parallel) branches in this circuit. The pushbutton switch only carries the coil current, while the relay’s switch contact only carries the lamp current.
{\bullet} Suppose the battery is rated at 12 volts, the lamp has a resistance of 3.2 ohms when energized, and the relay coil has a wire resistance of 240 ohms. Calculate the amount of current carried by the switch when it is pressed.
Reveal answerBear in mind that this is not the only possible circuit solution:
Challenge yourself by designing a different circuit to meet the same criteria!
Regarding the current calculation, a close look at this circuit reveals it to be a parallel combination of the relay coil and the lamp as the two loads. The two switches provide negligible resistance, so we can solve this as a simple parallel circuit:
$$I_{total}=I_{coil}+I_{lamp}$$
$$I_{coil}={V_{battery} \over R{coil}}$$
$$I_{lamp}={V_{battery} \over R{lamp}}$$
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Notes:Note how a schematic diagram was provided for you, to help you determine where each and every wire should go. In real-life situations, you may not be given any schematic diagram at all. In such cases, it is an excellent problem-solving strategy to first sketch your own schematic diagram, before attempting to sketch a pictorial diagram or connect real wires to the devices. The concept here is that schematic diagrams are much easier to interpret and understand than pictorial diagrams where wires tend to cross over each other more, and where components are not always optimally placed.
