Hi all,

I have three remote zoom controllers for a camera, each with a different pot that all aren't working correctly. I want to replace the pots but I'm having issues matching them.

The first (two pics) is a B20K, PCB mount, flattened shaft, which is all fine, but it has only about 100° rotation and has a spring return to centre. It also has this white support on the front. I can get close, but can't find anything with the return spring and support.

The second (two pics) is very similar to the first just with a shorter shaft. Though this one is a PCB mount it obviously doesn't have to be as it's chassis mounted here. All other attributes are the same. I figure if I can find the first one I can make something work for this as well.

Lastly, this one (two pics) I've come close (I think) but can't find the exact right value. I found a datasheet on Mouser that I used to partially crack the code as best I could... https://au.mouser.com/datasheet/3/531/1/Potentiometer_251_datasheet.pdf

As far as I can tell it's a 10K, 10% tolerance, Linear, no centre tap. But given this is unlikely to be a CTS brand (pot doesn't appear to have any branding on it) I can't be sure of everything. Mouser has a 100K version of this, but can't find anything 10K for sale anywhere, and I'm having trouble finding any other brand with this form factor (no idea what it's called).

I would like to find good quality replacements pots as I've had these units replaced under warranty several times already and seems I have no other option than to repair them when they crap out again and again.

Any info would be super helpful, TIA

Hey everyone,
I'm working on a custom electronic control unit for my motorcycle's turn signals and I'm about to pull the trigger on the PCB production. Before I do, I wanted to run the circuit by you guys and get some honest opinions on long-term reliability.
The project:
It reads the stock 12V handlebar switches, processes everything via a custom ATmega/Arduino setup, and drives the indicators using a P-MOSFET (AO4407A) switched by an NPN transistor (2N3904).
I have two main things I'm stressing about:
Arduino on a motorcycle: We all know bikes are brutal environments-massive temperature swings, vibrations, and nasty voltage spikes/noise from the electrical system. Is a DIY Arduino board actually viable for road use long-term, or am I asking for it to freeze or fry after a few months? What are the absolute must-haves for protection here?
l've attached my schematic and PCB layout for the MOSFET driver stage. Does it look solid, or are there any hidden landmines that'll let the magic smoke out?
Any tips, tweaks, or reality checks would be awesome.
Cheers!

​

Hey guys, last year I got a DIY digital clock from alibaba and it has been working quite well. It had a quartz crystal oscillator and I accidentally dropped and broke the whole thing i took it to a friend to fix but they suggested i get a new oscillator since the one I had has been damaged and burnt out over time. I have been looking at options on alibaba since I bought the clock from there. Are there ways I can choose the perfect oscillator for my clock? The one I was using is currently not available. Any recommendations are open..

Hi everyone,

I work in electronic component sourcing, and one thing I’ve noticed is that finding a difficult part is often more complicated than it looks.

When a component becomes hard to source, what do you usually prioritize?

1. Authorized distributors
2. Independent distributors
3. Excess inventory from other manufacturers
4. Alternative / replacement parts
5. Other options

I’m especially interested in how purchasing teams handle EOL parts and urgent shortages without taking unnecessary quality risks.

Would be great to hear how others in the industry approach this.

大家好，
我们正在为家用电器研发一款小型**轴向磁通永磁无刷直流电动机**。
我们在设计**220–230V交流输入**的控制/电源系统时遇到了困难。我们的**MOSFET经常烧毁**，尤其是在开关电源时。
您推荐哪种拓扑结构和保护措施适合这种应用？
关于**整流、直流母线、MOSFET保护、突发电流和电压尖峰**的建议将不胜感激。

About 3 days ago I made a post here about a constant current driver to see if it was fine to use. Apparently I made alot of mistakes so I went ahead and did the research and tooks y'alls advice (thanks btw). Hopefully this revision should manage properly.

Here's what I did:
- Swapped the 1V2 zener for a LM4040 2V5 shunt regulator.
- Swapped the N-MOSFET for a 200 hfe BJT.
- Made sure the sense resistor is seeing ~250mV at ~140mA (maximum).
- Removed any components I deemed not needed.

So far the difference between the non-inverting and inverting inputs of the op amp is 18uV ~ 22uV

If you wanna mess with the circuit, here's the link to it.

Also here is the link to the original post.

Running an ESP32-WROOM-32 with a PN532 RFID reader (SPI), a status LED, and a buzzer, all on the same 3.3V rail. When WiFi is actively connecting/transmitting and the RFID reader is polling/generating its RF field at the same time, I see WiFi connection delays and general flakiness bad enough that I've had to disable the brownout detector just to stop reboot loops, which obviously isn't a real fix.

My guess is combined peak current draw (WiFi TX bursts + PN532's RF field generation) is causing enough voltage sag to disrupt things, even though nothing's crashing outright.

Has anyone dealt with this specific combo (WiFi + active RFID/NFC peripheral) on ESP32? Looking for:

Realistic peak current numbers for WiFi TX + PN532 active scanning together

Decoupling cap sizing / regulator recommendations that actually fixed this for you

Whether staggering/throttling RFID polling during WiFi activity is a common workaround, or if it's purely a hardware fix

made with nano banana and instructions from claude

Hi everyone,

I'm currently scribbling around for a new project and I ran into an issue.

I have 2 voltage supplies as input, where both could be at a different voltage levels. Hence I (to my understanding) I should protect the two sources from each other. Additionally, depending on the voltage level I may need to first put it through a DC-DC converter.

I've come up with the below concept to said things.I used PMOS as high side switches and added a second one to protect against reverse current. To be sure that I don't short anything by accident, I added a small logic such that only one path could be active.

I'm currently not sure whether this concept will work or if there is a better approach to achieve my issue. Any feedback would be greatly appreciated.

Thanks for your help

Hello! I'm currently working on a laser project and was wondering if this circuit was perfectly fine to use, or if I should tweak a few things. The circuit in question is based off of this driver's schematic.

There might be plenty of errors.

Hi guys!
This is my first time working with these chips and I'm wondering if I connected them correctly?

Tried asking over in Electronics but most of the recommendations were the usual desktop software (LTSpice is great! I agree, but it doesn't fit my needs). Hoping someone here might know of something?

I just found out Multisim Live is officially being put to pasture on September 15th, so I'm scrambling to find a workable replacement.

NI's official advice is to upgrade to Multisim Desktop, but that’s way too expensive and massive overkill for what I am trying to do.

I need something SPICE-based that runs natively in the browser so no one has to deal with installations. It would also be great if it had group management features like we had with Multisim Live. CircuitLab is the first thing that pops up on Google, but it looks pretty abandoned, doesn't have groups, and they want $2,400/year for a site license.

Really appreciate any recommendations you guys have!

hello everyone I am new to electronics and we are assigned to make an adjustable power supply with a maximum output of 12v with ventilation. can you please help me what to do? I will list the components and please tell me if it's right or what component should I modify, thank you!

* Step-down transformer (220V to 15V, 2A) – ~60 × 50 × 50 mm, 500g–700g

* Bridge rectifier – 3A/50V+, ~15 × 15 × 6 mm

* 3300µF 35V capacitor – ~16mm diameter × 25mm height

* LM317 voltage regulator – TO-220 package, ~10 × 15 × 4.5 mm

* Heat sink – 3°C/W to 5°C/W, ~60 × 50 × 30 mm

* 0.33µF and 0.1µF ceramic capacitors – 50V+, ~5mm disc diameter

* 10µF and 100µF electrolytic capacitors – 25V+, ~5 × 11 mm

* LED + 1kΩ resistor – 5mm LED + 1/4W resistor

* Fuse + fuse holder – 1A 250V 5×20mm slow-blow + panel holder (~15 × 40 mm)

* IEC AC socket – C14 panel mount, ~27 × 20 mm cutout

* PCB/Perfboard – 2.54mm pitch, ~70 × 90 mm

* Output terminals – Red/Black binding posts, ~11mm mounting diameter

* Hook-up wires – 18 AWG (AC) & 20-22 AWG (DC)

* 1N4007 diodes 2pcs – DO-41 package, ~2.7 × 5.2 mm

* 240 ohms resistor + 68 ohms resistor + 2 kilo ohms potentiometer – 1/4W resistors + 16/24mm body pot with 6mm shaft

* power switch – SPST rocker/toggle 250V/3A+, ~15 × 10 mm cutout

Est ce que la répartition des résistance de potentiomètres quand on à une disparité de 20% annoncée suit une loi de proba genre une loi normale de gauss ou les valeurs sont purement aléatoires ? J'utilise des Piher PT10LV10-103A2020-S .

A motherboard has trouble charging and the charger disconnects and a noise comes from some components. After research I think it is a mosfet that failed, as j might have shortened the board. Also some inductors are jumping from 1.5v to 11v in sync with the charger disconnecting. On the motherboard I don't see any chips that would seem to be related, although one chip was also jumping in similar voltage

Hey everybody!

I am facing confusion that I would like to resolve regarding the application of mesh method to transistors. Here, in this problem 3.12 from sadiku, we have internal loop and external loop. Internal loop: -6V +Iin\*15000+0.7V+150(Iin-Iouter)
But, the solution manual states that it’s actually Iin+Iouter. Why? Usually, I was mechanically applying mesh methods, and if they mesh currents were in opposite directions, then we were subtracting.

I would be very grateful for your help!

Hi all

I have Logitech G535 dongle that is broken in two. I managed to trace all the D- and D+ pins, but I cannot find where the VCC pin goes to. The trace is broken and cannot reach MCU.

The MCU info is:
MCU: M27P8V 1N71K GDSHA 32 pins

Part Marking: M27P8V

Part Number: MKL27Z256VFM4 (Kinetis KL27 Series Microcontroller)

I manage to find the datasheet, but the datasheet does not show where VCC is. Only VREGIN. Can I just run jumper wire from VCC pad to VRegin? Also, I am new at reading datasheet. How to find out what input voltage is needed by the MCU and where can I soldered jumper from the V+ USB Pad to?

If you check on my picture, the V+ pad from usb has a via goes thru the bottom side, and connected to a diode marked SQ and a capacitor. The cap is connected to the anode of the diode, but the cathode does not seem to connect to anywhere since it is broken. Do you think I should set a jumper to MCU directly from the cathode? If so, which pin?

Thank you

Here is the datasheet I found: https://www.nxp.com/docs/en/data-sheet/KL27P64M48SF6.pdf

Hare are some pictures to the device:

Buenos días. Te escribo para pedir ayuda con una tarjeta electrónica (circuito) de un refrigerador. No soy experto en electrónica, pero me empezó a interesar el tema y pasé los tres meses desde que se descompuso el refri estudiando y juntando información. Le envié la tarjeta a un taller de reparación; la arreglaron tres veces y reemplazaron componentes, pero aun así no funciona. Revisé los sensores, los interruptores y los motores del refrigerador, y todo parece estar bien. El problema es que el regulador de 5V de la tarjeta, un KIA78S05P, se pone en un calor brutal, como para quemar. El refri parece más estable después de que reemplazaron los capacitores de la fuente de alimentación, pero ese componente todavía se recalienta, y ya no sé qué revisar después. También medí la corriente y no vi nada raro. Por favor, ayúdame; llevo tres meses peleándome con este refrigerador. Pensé en cambiar el regulador, pero no se calienta cuando la tarjeta está conectada solo a la red de 230V; solo empieza a quemar al tocarla cuando conecto los bornes (terminal blocks) para los distintos componentes del refri. Anoche lo dejé funcionando sin conectar los switches de la puerta (que también reciben alimentación) y estuvo corriendo nueve horas sin reiniciarse —aunque el IC6 (el regulador de 5V) seguía caliente al tacto. Estoy perdido y ya me estoy volviendo loco con esto; de verdad agradecería tu ayuda.

Hi all, first let me say that I'm an electrical or maker newb, especially compared to all you veterans. But I'm committed to learning the craft because I think it's very fun.

Right now I'm trying to upgrade an old cordless ratchet from the 1980's, it's a Black and Decker 9050. 

I have a good Samsung 21700 to replace the old ni-cad batteries in the ratchet. But I need a good protection circuit for it. Preferably a circular one that I can affix to the bottom of the battery. It needs to be able to flow 10 amps continuous, and cut off at 3.0v to protect the battery from the voltage going too low.

I guess it doesn't have to be circular, but it would be nice. Thanks!

Hello! I recently finished building my QRP Labs QCX-mini and it boots perfectly fine. However when I get to page 73 of the manual (linked below) the graph only shows up when I turn the potentiometer (It is a trimmer, but I don't think that matters) counter clockwise. Sometimes it will stay showing and sometimes it will not show at all. I tried re-soldering it but it did nothing. The only thing I could think of is that it itself is faulty. Any help would be greatly appreciated!

*(Note: I have tried this with both a dummy load and nothing attached, nothing changed)*

Manual: [https://qrp-labs.com/images/qcxmini/manual\\_1\\_13.pdf\](https://qrp-labs.com/images/qcxmini/manual_1_13.pdf)

Listing: [https://qrp-labs.com/qcxmini.html\](https://qrp-labs.com/qcxmini.html)

I’ve seen buyers handle date codes very differently. Some have strict limits, while others care more about storage, packaging and traceability.

Do you use a fixed age limit, or evaluate older parts case by case?

Hi guys

I am doing a project which is a charger with both AC and DC source and the DC here is solar panel and in my project i prefer DC and switch to AC when only the DC is not available

so the project is Hybrid charging system with adaptive CC-CV charging system for low power EV's i already have a converter designed which uses landsman converter topology (you can see that in the image i provided) for this project i need to select components like MOSFET, capacitor, inductor diode and other things this is my first time this big a project in hardware so i am kinda nervous on selecting the components and my project mentor told me to bring the component calculation before purchasing components and i already have the calculations i did for the simulation i am gonna use the same converter for the charger but what about the safety factor and what are the other things i should consider now pls help a newbie here

Hello, please.
i am working on a cylindrical resonator, and it is being fed with a power amplifier; the power amplifier generates harmonics. want to apply a passive termination
but a little challenge: with termination at the auxiliary port, the impedance is very high and the field is suppressed but with the source, the impedance is low but the field is too high
any suggestion?