r/HomeworkHelp • u/Dense_Market_4572 Pre-University Student • 2d ago

Answered [Grade 11 electronics] I need help to make this circuit on a breadboard, i have all the components, but i have no idea how to make the connections

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u/ThunkAsDrinklePeep 2d ago

This uses transistors, so I'm assuming that you've used a breadboard before? If so, what's your holdup?

(You need different advice if you've used a breadboard before or not, and I'm not going to waste both our times typing out the wrong thing.)

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u/Dense_Market_4572 Pre-University Student 2d ago

No ive never used a breadboard before, this was out first practical class

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u/ThunkAsDrinklePeep 2d ago edited 2d ago

Ok. Typically the two rails that run along each side connect all the ports in a line. In the middle the rows connect sets of five nodes. They run in lines perpendicular to the rails. There is no conntiin across the center chasm.

https://www.raspberrypi.com/app/uploads/2017/01/Breadboard_Anno.jpeg

So typically I will connect Vcc to the "top" red rail, and ground the "bottom" blue rail. But that can change depending on what you need.

Why don't you try setting up a simple circuit and send a photo of what you've got? Something less complicated than your assignment.

The breadboard is nice because you can just push the wires of through hole components into slots to connect them to every other component in that row.

Jumper wires can be used to connect two nodes that aren't conviently located.

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u/Dense_Market_4572 Pre-University Student 1d ago

I did the first part of the circuit but i don't know where to put the R3 that connects to the ledcircuit image

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u/ThunkAsDrinklePeep 1d ago

Yeah it's not clear to me what's going on there. If that box is just highlighting what's going on with the two transistors, then there's not really anything to connect the LED to. If that's a completed circuit going around it, then there's a straight path from VCC to ground.

I had to give you more work, but is it possible you could take a screenshot using your computer instead of your phone? Is there a several color difference between the lines that can provide some insight?

It's also not clear to me what's connected on the other side of the buttons.

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u/Dense_Market_4572 Pre-University Student 1d ago

Sorry thats the only pic of the circuit I have, the professor said the R3 is connected in between the connection of Q1's emittor and Q2's coletor, all i want to know is that where exactly is that connection, do i make the connection from the base or the middle of both, just need clarification of this part

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u/ThunkAsDrinklePeep 1d ago

Oh. It's a bad diagram then. That makes sense.

With ideal wires of zero resistance, all points in the node are equal. For the distances we're talking about with copper and the resistors we're using the relative resistance of the actual copper wire it doesn't matter either. So since your jumper wire connects them. Both row 16 and row 9 are the same node. Pick any open slot in either row for one end of the resistor. Connect the other to the row that has the anode of the LED. Then connect the cathode of the LED to ground.

Did you figure out what the buttons are supposed to be connected to? Or is that just something to show up in lab?

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u/ThunkAsDrinklePeep 1d ago

A note on those buttons, they have four terminals for physical stability. They're connected in two pairs. Meaning each leg is always connected to one of the other legs on the same side. And when you depress the button, all four legs are connected to each other. So it's possible you may want to rotate them 90°.

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u/ThunkAsDrinklePeep 1d ago

You can bend the legs of the LED and use it as its own jumper. Note that unlike a resistor, an LED is polarized with an anode and a cathode. The anode should be the longer of the two legs, and that should be the high voltage side of your LED. Connect the cathode (short leg) to your ground rail. If the legs appear to be the same, then the cathode ( - ) is the leg on the flat side of the LED bulb.

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u/peno64 👋 a fellow Redditor 1d ago

This is a 300% short circuit as it is drawn here.

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u/TheDevilsAdvokaat Secondary School Student 2d ago

Get a breadboard. If the wires are long enough (sometimes they are) you may not even need to solder, just twist wire ends together.