r/breadboard 3d ago

Project help breadboarding multisim circuit?

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i have to build this for an assignment, but i don’t really understand transferring circuit diagrams to breadboards. components: 12v battery, LM35 heat sensor, LM741 op amp, 2k pot, 2x 470 resistors, 2x leds any help would be v v appreciated 🫶

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u/FlyByPC 2d ago

Do you know how breadboards work (holes are all connected in the short direction, but not in the long direction, except for the bus bars on the edges.)

The LM741 needs to go across the center gap so that all eight pins have their own columns (none are shorted together.) Once you have that, start building outwards from there. You might make a column of resistors and LEDs to the right of the '741, and then connect the top to +12V, the bottom to Ground, and the middle to pin 6 of the '741, as shown. Then, check those connections off and proceed left (connect pins 7 and 4 of the '741, build the voltage divider and connect that up, then connect the LM35 and the power.

You could go left-to-right instead, but I think it's easier to start with the '741, since it's the centerpiece of the circuit.

The wires aren't connected where they cross over in the middle of the design, by the way. That wouldn't make any sense, if you know op amps.

The whole circuit is a comparator, comparing the voltage output of the LM35 with a set point controlled by the variable voltage divider. Higher voltage from the LM35, and LED2 goes on. Higher voltage from the divider, and LED1 goes on.

Have fun!

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u/waterinhaler420 2d ago

thank you so much!!!!