Drawing the Schematic for a Circuit I built on a Breadboard

• Engineering
In summary, the system is designed to switch on external lighting in a sports stadium when the ambient light level falls below a certain value. Various monitoring indicators are to be included, such as a light dependent resistor to determine ambient light levels, a red LED to indicate when the light is below the set value, a green LED to indicate when the light is above the set value, and an orange LED that flashes when the ambient light level falls below a certain level. If the light fails, an indicator is to flash indicating that the light should be turned on.
Homework Statement
Relevant Equations
i am now trying to draw the circuit for this but struggling
Hi, I have built this circuit on a breadboard and have tried to draw it out but I am pretty sure its not right, needs to include- 741 amplifier,transisitor, NAND gate, 555 timer or NAND gate (for the orange LED)
this is my attempt, can somebody help as I am new to this

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What in the world is that supposed to be?

Well, usually one designs a circuit schematically and then implements it on a breadboard to see if it works not vis-versa as you have done. Does your circuit do what you intended? We need to know the function and then we can decide if it is a reasonable circuit. Of course, it is possible we might be able to determine if it will do nothing or even self destruct.

i am now trying to draw the circuit for this but struggling
Hi, I have built this circuit on a breadboard and have tried to draw it out but I am pretty sure its not right, needs to include- 741 amplifier,transisitor, NAND gate, 555 timer or NAND gate (for the orange LED)
this is my attempt, can somebody help as I am new to this
View attachment 275369
I think it looks reasonably clear. I think you have a LDR which will turn on a opto-coupler and light an LED.

Unless I am seeing a line in the schematic that isn't there, the LED will always be lit.

If you are asking how a schematic should look, here is an example from the real world. Yours may not need to be as sophisticated (drawing format, notes, etc.) but the clear communication of what's in the circuit and how they are connected is important.

berkeman

i am now trying to draw the circuit for this but struggling
Hi, I have built this circuit on a breadboard and have tried to draw it out but I am pretty sure its not right, needs to include- 741 amplifier,transisitor, NAND gate, 555 timer or NAND gate (for the orange LED)
this is my attempt, can somebody help as I am new to this
View attachment 275369
Where the lines cross to the right of the 741 there should be a dot indicating it is a connection.

DaveE said:
here is an example from the real world
What is the *.webp extention from? My Firefox browser opens it no problem. Just curious...

berkeman said:
What is the *.webp extention from? My Firefox browser opens it no problem. Just curious...
No idea. It's a jpg on my hard disk, when I hover over the post, and when I do save as from the post. A PF site thing, a Firefox thing?

berkeman
berkeman said:
What is the *.webp extention from? My Firefox browser opens it no problem. Just curious...

from: https://filext.com/file-extension/WEBP ...A great resource to bookmark.

"...primarily associated with Web Browsers by Google."
"It can achieve smaller sizes than the current standards ... at 25-34%..."
"...Chrome and Opera offer native support whilst others may require JavaScript libraries to display WebP images."

The above entry reads as if it was written when .WEBP was brand new. Unfortunately no date is given on the page.

Cheers,
Tom

berkeman
the circuit is intended to match this
controller is required to monitor the natural illumination of a sports stadium and, when the ambient light is below a pre-set level, to switch on external lighting. The system is required to be of high integrity, and various monitoring indicators are to be incorporated as specified below.

Furthermore, the status of the light (Large white LED) is to be monitored, and if this should fail, when the lighting should in fact be on, a warning signal is to be given in the form of a flashing orange LED.

Circuit Requirements

1. A light dependent resistor (LDR) is to be used to determine ambient light levels.

2. A red light emitting diode (LED) should illuminate whenever the ambient light level is below the pre-set value.

3. A green LED should be illuminated if the ambient light is above the predetermined level. Note, the use of two LEDs in this manner serves to indicate that power is applied to the system, as one LED will always be on.

4. An orange LED is to flash on and off repeatedly, in the case that the ambient light level is low, and the white LED is not illuminated, i.e., it has failed.

5. Individual functional blocks of the circuit should be constructed and operation verified on breadboard. One example of such a component block may be the LDR and comparator light detection circuit

Last edited by a moderator:
Two threads on the same problem have been merged together
A controller is required to monitor the natural illumination of a sports stadium and, when the ambient light is below a pre-set level, to switch on external lighting.

The system is required to be of high integrity, and various monitoring indicators are to be incorporated as specified below. Furthermore, the status of the light (Large white LED) is to be monitored, and if this should fail, when the lighting should in fact be on, a warning signal is to be given in the form of a flashing orange LED.

Circuit Requirements

1. A light dependent resistor (LDR) is to be used to determine ambient light levels.

2. A red light emitting diode (LED) should illuminate whenever the ambient light level is below the pre-set value.

3. A green LED should be illuminated if the ambient light is above the predetermined level. Note, the use of two LEDs in this manner serves to indicate that power is applied to the system, as one LED will always be on.

4. An orange LED is to flash on and off repeatedly, in the case that the ambient light level is low, and the white LED is not illuminated, i.e., it has failed.

5. Individual functional blocks of the circuit should be constructed and operation verified on breadboard. One example of such a component block may be the LDR and comparator light detection circuit.

Circuit Design Suggestions The following points are suggestions as to the circuitry you might choose to use, and are based on the material covered in recent lectorials and introductory practicals which assumes a knowledge of operational amplifiers, NAND gates, light dependent resistors (LDR), 555 timer and transistors. However, other circuitry may be used, but you should discuss this with the class tutors and/or technicians before

implementation.

1. A single 12-volt power supply may be employed.

2. The circuit may be built in a logical form, that is, one functional block at a time, in order that each stage may be built and tested before the following block is constructed.

3. An operational amplifier may be used as a comparator to “digitise” the voltage across the LDR light sensor.

4. A transistor may be used to switch power to the large white LED.

5. The voltage across the LDR may be monitored by an operational amplifier configured as a comparator.

6. A NAND gate may be used to gate the “white LED” signal with the ambient light status.

7. A NAND gate or a 555 timer may form the basis of the oscillator required to drive the orange LED.

here is my ATTEMPT

Last edited by a moderator:

Related to Drawing the Schematic for a Circuit I built on a Breadboard

A breadboard is a device used for prototyping and testing electronic circuits. It is a flat board with holes arranged in a grid pattern, into which electronic components can be inserted and connected using wires.

Why do I need to draw a schematic for my circuit on a breadboard?

Drawing a schematic helps you visualize and plan the connections between components on your breadboard. It also serves as a reference for troubleshooting and making changes to your circuit in the future.

How do I draw a schematic for my circuit on a breadboard?

Start by identifying all the components in your circuit and their connections. Then, draw a diagram using symbols to represent each component and lines to show the connections between them. Make sure to label each component and connection for clarity.

What are some common mistakes to avoid when drawing a schematic for a breadboard circuit?

Some common mistakes include not labeling components and connections, using incorrect symbols, and not following the correct layout of the breadboard. It is also important to double-check your schematic for accuracy before building the circuit.

Can I use software to draw my schematic instead of doing it by hand?

Yes, there are various software programs available for creating circuit schematics. These programs often have libraries of electronic components and allow for easy editing and sharing of schematics. However, it is still important to understand how to draw a schematic by hand for troubleshooting and understanding circuit design principles.

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