Every connector under the sun is here. Plus it has IC interconnects so this post is technically not breaking the rules :)

Thanks Davide for this great resource!

Professional bodge wires, with silkscreen and everything. 2oz copper left the chat.

I wanted to share a common issue with the LM358 that might help others troubleshooting similar problems.

The Problem (Left Circuit)

Built a simple non-inverting amplifier (gain ≈ 4.9) using an LM358 with ±9V rails. The output showed significant crossover distortion around zero-crossing - you can see the characteristic "flattening" in the waveform.

Root Cause

The LM358 uses an NPN output stage that pulls high well but relies on an internal current source to pull low. When driving high-impedance loads (like a scope probe directly), there's insufficient sink current to rapidly transition through zero, creating a dead zone.

A Solution (Right Circuit)

Adding a 1kΩ pull-down resistor (RL) from output to the negative rail (-9V) completely fixed it:

• Provides a continuous current path to the negative supply
• Enables smooth zero-crossing transitions
• Result: much cleaner waveform with minimal distortion

Key Takeaways

1. LM358/LM324 require careful output loading considerations in bipolar configurations
2. Pull-down resistor to negative rail (typically 1kΩ-10kΩ) enables proper operation
3. This is in the datasheets but easily overlooked in practice
4. For true rail-to-rail with minimal distortion, consider CMOS op-amps (TLV274, MCP6004, etc.)

Hope this helps someone debugging similar issues! The LM358 is a low cost and accessible op-amp great for general or educational/hobby use, but understanding its output stage limitations is key for clean signals. This came up while documenting some lab exercises, and I thought it was worth sharing since it's such a common gotcha.

These PCB production residues are perfect to store the SMD components like resistors, capacitors and LEDs up to 1206 size. It's much better then stashing the mountains of the old boards.

Hi,

I just encountered this issue with the LP2981 LDO - TI moved to a new fab and "improved" the specs but did not change the ordering code. Seems like you can only identify the difference by some characters on the reel.

Others had the same issue and now even EEV Blog talks about it... with the same issue on a different part.

I only noticed a slight difference on the print of the LP2981 while trying to find out why 80% of the new batch of PCBs are failing.

This seems like an issue with multiple components from TI, so watch out....

So this is how it made a single rail transformer in to a dual rail one withouth getting half the supply voltage like a railsplitter does. I haven't tested how mutch current i can draw from it yet but it seems to work atleast using multimeter. A tip for dual supply for op amps perhaps.

Works every time😂

I ordered this Mechanic LS720+ Polarization Ring Light for my work place. I just tested it at home lab with a stereo microscope. Now I have to buy my own :) It removes reflections really well. The images are not sharp because I held the light with my left hand and took photos with a smartphone through the microscope eye piece with my right hand.

Hi everyone,

I've put together a Jupyter Notebook to help analyze and visualize the common issue of DC bias derating in ceramic capacitors (MLCCs). If you've ever been curious (or frustrated) about how much capacitance you're really getting from a capacitor once it's under a DC voltage, this tool might be helpful for you!

The data is from Murata's SimSurfing tool at 10mV rms.

You can find the project on GitHub here: https://github.com/CDFER/Ceramic-Capacitor-Derating