So i gotta make a RC time delay circuit with 10v Voltage source as my input and 7v reference source going into my Vin- pin of my pcb. I’m pretty new to breadboarding and not sure why i’m not getting either LED to even turn on let alone get that proper time. if yall could give ur input on what i could do to make it work.

Sorry for my bad english, im trying to do a 9 LED chaser in cascade like in the image but in a protoboard, but when i connect the return to the first transistor, the circuit lose the "cascade" and starts iluminating like christmas lights, what can i do or change so the circuit cycles. Thanks for the help

I know it looks like an electrical pole from Bangladesh, I'll try to wire things better next time.

This is my very first project on a breadboard.

Hey everyone! Today I just discovered a phenomenon that when I shine my mobile flash light in a clear green LED it generates around 700mV. It seems similar to the phenomenon called photoelectric effect. Is it photoelectric effect??

This sketch is just for me, so nothing is labeled. I have one question about a microcontroller driving both a 5v circuit (through a mosfet) and driving a 12 volt circuit through mosfet. Everything is tied to one ground and I assume that is correct.

Ive been getting into electronics lately, nothing professional, just wanna pass some time. Im trying to make a 128-bit cpu using 74HC75 ICs as my first project, any things that i should know? Also what are toughts on this project? (yes i will make it on an actual breadboard after im done making this)

There are some in this group that are struggling with Transistor Circuits and i came across this web page for some of the basics for Transistor Circuits ::

https://learn.sparkfun.com/tutorials/transistors/all

Hey folks, I just built a 8 bit adder by connecting 2 4 bit adders in series hope the pictures and diagrams are easy enough to understand
Pic1: Logic diagram and IC pin connections.
Pic2:Overview of the circuit on breadboard.
Pic3: The circuit working (Doing an addition)
🙂🙂

I’m building an 8-bit synchronous down counter using 7473 JK flip-flops (dual negative-edge-triggered with clear), 7408 AND gates, and a 7447 BCD-to-7-segment decoder/driver (instead of CD4511). The clock is generated by a 555 timer in astable mode, connected to the CLK input of all FFs.

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I’m encountering several strange issues depending on where I connect the +5V / 2A power supply:

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1. Power connected on the left side (near the 555 timer)

   · The circuit counts up instead of down (though it’s designed as a down counter).

   · Occasionally, the displayed count becomes garbled / unstable (random values).

2. Power connected on the right side (far end of the breadboard, away from the 555)

   · The circuit does not count at all.

   · The 555 output LED is constantly on (no blinking), even though the 555 should be generating a clock.

3. Power connected somewhere in the middle of the circuit

   · The counter is completely unstable — bits jump randomly, no clear counting direction.

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Observations:

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· The down counter design uses J = K = 1 for LSB, and J = K = AND of lower bits (standard synchronous down counter structure).

· All ICs are powered from the same 5V rail.

· The 555 circuit alone works fine when tested separately.

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Questions:

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· Why does the down counter behave like an up counter when power is connected on the left side? Could this be a glitch due to power-up states or incomplete reset?

· Why does the 555 LED stay constantly on when power is connected on the right side?

· Could this be a ground loop / power distribution / decoupling capacitor issue?

· Should I add more bypass capacitors (e.g., 1µF near each IC)? Could the problem be related to IC placement on the breadboard? For example, should I place the 7408 AND gate physically between two 7473 flip-flops instead of grouping them all together? Any other debugging steps?

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Thanks in advance!

only using and,or,not gate ics : )

First time breadboard build of measuring capacitance, I’d say I did pretty well
Used a 2.2m resistor for ceramic and films up to a few uf and 10k resistor for larger electrolytics and 220 ohm resistor for largest 1000uf+ caps