I want to replace this capacitor. There is a 0 with a line under it, not sure what that means. Could anyone point me to a suitable replacement? Its for a temperature gauge. Looks like it says:

W

620 J

Thanks

Working on a small motor driver circuit and I keep seeing designs where two identical MOSFETs are placed in parallel rather than swapping in one higherrated device. I get that it spreads the thermal load across two packages but I'm trying to understand if there's more to it than just heat.

My current setup runs about 8A continuous and I was going to grab a single FET with a 20A rating and call it done. Then I looked at a reference design from a reputable manufacturer and they used two smaller FETs in parallel instead, which made me second guess myself.

A few things I'm not clear on: does paralleling help with gate charge and switching speed at all, or is that actually worse because you're now driving more total gate capacitance? And is there a real risk of one FET hogging current before they thermally balance out, especially during startup or fast switching?

I've checked the Rds(on) specs and they're close but not identical between the two devices I have on hand, which is what got me thinking about this more carefully.

Not trying to overthink a simple motor driver but I'd rather understand the tradeoff before I commit to a layout.

I am making a battery powered robot using a ESP32 microcontroller to control 2 servo motors. This is my battery "management" circuit I've come up with. It is responsible for charging, protection and powering the load. I have bought all the components, wired it up and tested, and it works fine. I'm looking for ways to improve it or to learn about other ways to do it. "It" being on/off control, output to the load, protection and charging.

The idea/circuit is as follows:

• 3s battery pack made of individual 18650 cells.
• Goes through a 3S BMS for protection.
• Charger and load cannot be connected to the batteries/BMS at the same time, otherwise the charger will try to drive the load, which it is not meant to do.
• All grounds are always connected. Rocker switch controls whether battery (BMS) positive terminal is connected to the load or to the charger.
• When connected to the load, it cannot charge.
• When connected to the charger, the load cannot be turned on.
• Load goes to 2 separate buck converters, one making 6v@10A for the servo motors, the other making 5v@1A for the microcontroller.

Questions:

• Overall, is this fine?
• Not a question, but a note. Learned afterwards that even though the BMS lists itself as an all-in-one solution to protect and charge the batteries, it does not charge the batteries, at least not directly. A battery charging device can charge the batteries through the BMS is what it should say.
• While writing this post, I realised that the charger probably could power the load, since the output of the charger would be the same as the 3s battery pack. Only problem would be that it can only supply 2A of current, whereas I need maximum 8A for max load on the servos. Is this true? Could I power the system through the charger, IF the charger could output a high enough current?
• How do other battery powered devices manage this? Other devices can be used and charged at the same time

Side note, when charging the batteries through this system, an led goes on to show that it is charging. After 1.5hrs, it goes off and a different led goes on to show that it is done charging. But then for next hour, it alternates between done charging and charging, in about 20 minute intervals. After an hour has passed, it stays in the charge done state.

first of all my 200mA fuse broke and the 10A fuse still working (checked with continuity) so I decided to check the current using the left connection...in the picture 1 I broke the circuit to measure current and as you can see in the picture 2 the reading is zero .. why is that even though the fuse the left side is working?...how to fix that .

I need to know which component is this. Overvoltage caused this

EDIT: https://datasheet.lcsc.com/datasheet/pdf/0b1294f8e47a42e4ad7533d6477ab28a.pdf?productCode=C172766
I'll try this one. If it works i'll post on here

I originally made a mistake in my simulation, I've fixed it and now the voltages make sense. And the label of "Level Shift" now makes perfect sense.

But I am still interested in what this transistor arrangement is called, and why it might be where it is. Considering FOCUS_REF is set by a pot, so could be adjusted to anything that's appropriate

The signals are DC

I am creating a light sensor with a photodiode and OPA381. This little board goes on top of a ADC module for further data analysis.

Now I may need to use a guard ring for the sensitive output of the photodiode. But what is it exactly and how do I design this guard ring? Does it hold a certain voltage level or ground? Any info would be appreciated!

My wife's laptop wouldn't boot last week, figured the problem to be the cable from the power adapter that I later learned had a name lol.

Got one ordered and installed and the laptop is fine. Me being me, I decided to tear into the old cable and see if I could learn anything. Found basically what I expected, the sleeve was just holding the wires however at the jack itself there was a yellow hardened gel (I assume an insualtor?) where everything was soldered. My question is 2 parts, can I solder this and have it work, and will it be safely usable without that gel? The only wires not connected are the white and yellow

Hello everyone,

My company asked me to hold a basic electronics course for our employees. I’m planning to start with foundational concepts like current, voltage, power, resistance, capacitors, how to identify components, Ohm's Law, etc.

The audience consists of colleagues from the sales, pre-sales, and customer support departments. In short, people who don't have a background in basic electronics and don't need to dive into deep technical details or complex topics.

If you were attending a course like this, what topics would you want to see covered?
Thanks!

This isn't a common resistor, I was just wondering its resistance, and yes, based on the color code it's supposed to be 0.39Ω, which when measured with multimeter it is that. Orange White Silver.

1.4Ω resistor reading

1.0Ω lead resistance

We're a small startup and we're looking to design a high-speed PCB and we have two markets (locally and Europe) that we want to target.

In our own country, we have very high tariffs on imports and exports, so we're in a dilemma. If we manufacture and assemble it locally then it will become too expensive to export. If we manufacture it in China, it will be too expensive to import. If we have to design two layouts then that just increases engineering cost.

Is it just a matter of luck to find two manufacturers with identical stackups or is our only option here to make two different variants?

SMD newb here, this is a dev board for an accelerometer that uses certain caps for filtering (eg an RL), however I would like to eliminate these caps. C1-3 near the middle.

1. Desolder them, solder in tiny jumper wire OR
2. Reproduce this board without caps in place OR
3. Do some other option I'm unaware of?

I have a Geekworm x1009 Sata HAT connected to a raspberry pi 5 used as a NAS with 4 3.5" HDDs.
The specifications for the HAT require 12v 11a via a 3521 DC Barrel (peak) when used with 4hdds.

For better cable management and adding a Noctua Fan I think about using an SFX Psu with 450w.
My plan is to use a Molex (should offer exactly 12v 11a) as power supply for the HAT.
But it seems like there are no 3521 male DC Barrels supporting 11a (except some Chinese ones that look cheap and I wouldn't trust that they really support >5a).
So, my question is:
Are there any 12v 11a male dc barrels that I oversee?
Is the female dc barrel jack soldered to the x1009 really safe?
Should I use the sata power supply from my psu (only 3 connectors offered by psu) and power the missing one via the hat? And in this case - would the typical dc barrel jacks (max 5a) be enough (data sheet of hat says 5a for two 3.5" HDD, so it should be fine)

Thanks for any advice, I'm kind of stuck at the moment.

Hello!

For context, I'm not a technician - though I've built a few breadboard projects in my life and some electric guitars. Generally would describe myself as "knows just enough to get in trouble".

I'm currently going through the process of deep cleaning, lubricating, and inspecting a really cool portable console from "Audio Developments" made in the UK in the early aughts. Outside of a couple sticky buttons/ scratchy pots the thing works beautifully less one problem: there is pretty bad SnR on the main output which is transformer coupled. The monitor outputs are just fine and don't have that same problem. I figured it's very possible it will need experience professional to work on it but I also wanted to at least pull it apart. Inspect and clean everything before handing it off in order to rule out the obvious.

I'm looking at this daughter board that connects the power supply to the rest of the board and I'm seeing a couple nasty looking solder joints. It's possible they're just lead-free or something but I wanted to get some feedback from this community. In the photos the first couple are the daughter board with the joints that look bad to me, some photos of the actual external power supply, the placement of the daughter board in the case, and then some photos of the modules, and finally what it looks like when it's all together.

Beyond that, if anybody has any suggestions on how to determine what could be causing this humming/ buzzing on the main transformer coupled output. I welcome any feedback.

Hey all,

Has anyone here dealt with moisture detection on USB-C ports? I have an outdoor-rated electronic device in design right now, and I'm using the native USB-PD negotiation capability of an STM32. This does a lot but it doesn't give any kind of moisture detection, and I want to avoid energizing the receptacle when it's wet (there will be a cover over the port when not in use, but it's inevitable that someone will get it wet, and electrolytic corrosion would be bad).

Ideas I've had involve using a secondary USB-C protection IC e.g. Infineon EZ-PD but the BOM cost is as much or more than my actual microcontroller.

Another idea is to sense leakage on the CC (or other pins in the USB-C cavity near the power pins) using the CC1/CC2 ADC readings available. Sounds plausible, but I can't find a lot of documentation on how to do this, or whether a small current leakage path will even be detectable. Unclear from the datasheet what the input impedance of the CC1/CC2 analog sense inputs is even.

Any experience or pointers here welcome.

LED par stopped working after a beverage got spilled over it, now I cleaned every pcb and reconnected everything but nothing happend. I measured the dc output of the board but there was none. I tested the resistance of the +\ grnd of where the big capacitors are on, theres none. Can anyone give me tips on how to find the broken part or how to repair it? Thanks a lot

Replacing the battery in my Yamaha sy77 and I noticed this

Hi everyone,

I'm currently trying to repair an old Disney toaster. The toaster itself works fine, but the audio module, which is supposed to play a tune right when the toast pops up, first started sounding distorted/weak and has now stopped working completely.

Here is what I’ve tested so far:

Checked everything visually. No burnt parts as far as I can see.

Speaker: The speaker itself is working. Made clicky noises when I put a batterie on it and resistance measurement was 7.8 Ohm (Supposed 8.0 Ohm).

Sound Board Voltage: Tested DC voltage on the small sound board (where the red/black power wires come in from the main board) while pushing the toaster slider down and also while the toaster pops the toast (that’s where it should play the sound). 0.0V there.

Conclusion so far: Problem is probably that the main board doesn’t supply voltage to the sound chip after toasting the toast.

So my question is what I should test next? Or maybe someone knows what the probable cause is?

Thanks in advance for any tips!

Need to know what the male side is called. It is used for a fan.

I am trying to fix the board for the VCR4000 Nilfisk/Flexit central vacuum cleaner.
Found that L11 coil is blown, probably because IC TNY274PN is blown as well.
However, I am not sure how to read this value. Looks like K is tolerance, like at the MLCC capacitors, but I'm not sure about the inductivity, is it in mH or uH?

Hi all,

I own a Chinese BGA rework station - the Honton R490.

It's had one particular issue since I purchased it new. During the rework profile, usually between stages 2-3 or 3-4, the bottom hot air will drop from the set temperature of 320c to 220c, and then overshoot well past the set temperature to 420c. It'll remain at this temperature despite the profile set point.

The temperature of 320c is the only setting for the bottom hot air throughout the profile. Stage one has it go for four minutes, along with the IR plates at 200. In stage two, the top hot air goes from a mostly inert 50c to 200c for one minute. The profile then typically concludes in stage three with the top hot air increasing to 230c. During this stage, however, the unusual behavior ensues.

I am not at all familiar with PID controllers. I would very much appreciate it if the knowledgable engineers of this subreddit might be able to point me in the right direction as to how this issue can be fixed.

Thank you!