AND Gate Circuit on Breadboard Simulator

Thread Starter

BBF03

Joined May 4, 2020
1
Hello!
I have to build this circuit diagram in Breadboard Simulator v1.0. I haven't got the chance to work on a breadboard before so I do not know how to connect the components, especially the transistors, in this simulator. I have built series and parallel resistor circuits and they came out fine, but for this diagram I really need some indications on putting the wires and the components.
Thank you in advance!

schema.png
 
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Delta prime

Joined Nov 15, 2019
576
Hi there. Does your breadboard look similar to the photo
Breadboards are an incredibly useful prototyping tool, and the more you use them, the more you'll get from them!


1588594988907.jpg
 
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Ramussons

Joined May 3, 2013
890
Caution. You will have to put a suitable resistor in series with the LED. Else, the best that can happen is that the circuit won't work, worst you'll get a burnt out LED.
 

bertus

Joined Apr 5, 2008
20,883
Hello,

As @Ramussons said, the led will need a current limiting resistor.
A 220 Ohms resistor will likely do.
Also the values of R3 and R6 are to high.
Try 2k2 resistors for them.

Bertus
 

dl324

Joined Mar 30, 2015
11,899
Welcome to AAC!
but for this diagram I really need some indications on putting the wires and the components
Schematics are easier to read when unnecessary wire jogs and scenic routs are avoided. They're also easier to understand if you use component symbols that are more logical (inputs primarily on the left and outputs primarily on the right) and flow is predominantly from left to right and top to bottom.

This is how I'd draw your circuit:
clipimage.jpg

I swapped the position of the two transistors because order doesn't matter and it made for a cleaner schematic.

EDIT: There's a typo on R4, it should be 22k (per the original schematic).

I'll redraw your schematic soon to show how you could have made it easier to read, even with the poor timer component.
 
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Alec_t

Joined Sep 17, 2013
11,748
Welcome to AAC!
Your symbol for C1 is unlike the more conventional one (as in post #7). Is Breadboard Simulator being provocative?
Having Q1 as a circuit node designator and as a transistor designator is not good practice.
 

Audioguru again

Joined Oct 21, 2019
2,079
Dennis, the LED #1 needs a current-limiting resistor added, because the output current of an original old 555 is at least 200mA.
Also, the value of R3 should be changed to 220 ohms.
 
in the breadboard shown in post #2, the 5 verticals are connected together. A DIP package usually straddled the middle depression allowing 4 extra contacts.

The RED and BLUE lines are connected across. All red and all blue. Red is not connected to blue.

One Caveot is that not all breadboards of this style are the same. I'm used to ones that have a split half-way across, so you have 4 horizontals (2 red) and 2 blue.

Breadboards add capacitance. Don't force wires.
 

Tonyr1084

Joined Sep 24, 2015
5,249
My take on what I saw: Green (Verdi) LED, typical Vf (Vf = Forward Voltage) of 3.2V. Two transistors (2n2222), each with a voltage drop of about 0.6 to 0.7 volts. Starting with 5V; 5 - 3.2 - 0.65 (average) - 0.65 = 0.5V. Divide that by 220Ω and you get a current of 2.3mA. I don't know how bright that would make that LED. Ignoring the two transistors, you get [(5-3.2)÷220]=8.2mA. That's enough to make an LED glow fairly bright. But I don't know how bright an LED will glow with only 2.3mA.

D1 (Red LED) has a drop of about 2Vf. To make it equal in brightness to the green LED you'd need a resistor [(5-2)÷0.0082]= 365Ω. Using a 300Ω resistor would produce a current of 10mA. Close to your 8mA target (assuming that's your target current).
 

dl324

Joined Mar 30, 2015
11,899
Cleanup of the original schematic:
clipimage.jpg

I corrected the polarity of the capacitor symbol.
 
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dl324

Joined Mar 30, 2015
11,899
Dennis, the LED #1 needs a current-limiting resistor added, because the output current of an original old 555 is at least 200mA.
Also, the value of R3 should be changed to 220 ohms.
I didn't make any attempt to correct the circuit. The control pin should have a capacitor on it so noise isn't coupled to that pin. The values for R3 and R4 are too large.
 
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dl324

Joined Mar 30, 2015
11,899
I downloaded fritzing to do a layout; what a painful-to-use-program...
1588640804756.png 1588640301238.png

Was going to try to cleanup the layout a bit, but the dang program crashed so many times that I gave up.

EDIT: Just noticed that the transistor pinout didn't look right. This is terminal order I selected; backwards from what it should have been. There are also some spurious rats nest wires on R1, R5, and between pins 6 and 7 on the timer (wondered what they were).
1588643181510.png
 
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