As built it works great for it's designed purpose (ceramic pickup to ceramic input compares well to ceramic pickup through circuit to magnetic input).

Source

I opened a package from Amazon with a Dell OptiPlex 7050 and it was rattling. So I opened it up and I found this blue component. Does anybody know what this is? Is it something important? Do I need to fix it? Do I need to reattach it to something?

Hi there,

I want to use multiple ESP32s to scan WiFi and BLE packets for a people-counting estimation product.

I have already done this successfully with a single ESP. However, as there are multiple channels to scan, I'm thinking of adding a few other ESP32s and dedicating them to certain channels for improved performance. ESPs are cheap!

My problem is that I can, of course, give each ESP its own dedicated antenna, but this increases the cost, and it doesn't scale very well with the number of external antennas needed.

Ideally, they would all share the same antenna, but I don't know if this is possible?

All radios should only ever be receiving, not transmitting.

1. Is this possible?
2. Although I say all radios will only ever be receiving, are there any simple protections (PCB components) I can add to protect each radio should one accidentally transmit?
3. Is adding multiple ESP32s even the best approach to this solution, or is there a better approach to multi-channel wireless scanning? I'm not really wanting to do any high-performance wireless packet analysis; I just want to capture more packets more quickly for counting.
4. Slightly unrelated.. The ESP32 modules are RF pre-certified; however, does connecting them in this way, such that the RF path is introduced into the PCB, void this certification?

Thanks a lot :)

I'm trying to learn more about testing and exploring electronic devices and how to use my tools safely.

I have a smart body scale that seems dead. The batteries I used are rechargeable, my partner said the device was working with them before, but after a recharge the scale no longer seems to like these batteries. The rechargeables are rated 1.2V (1.3V reading when full) but the scale expects 1.5V, with 4 batteries in series for a total of 6V. It doesn't say the expected amperage draw though.

A quick search suggested that the upper current bound for most AAA batteries should be around 1A. When I plug my bench power supply into the terminals set to 6V and OCP set to 1A, it immediately triggers OCP. I tested the scale's terminals with a multimeter to see if they're shorted, but they're reading 100 ohms. My loose understanding is that OCP triggering means that, even for a moment, the current exceeded 1A.

If that influx current is normal, then how do I safely step up OCP to keep me from frying this scale? Should I try measuring the influx with my oscilloscope and a shunt resistor? After testing all this what would you start looking/probing for on the circuit board next?

Hey guys. I am looking for a 5k ohm potentiometer that has a hole through the middle. I know they exist as small packages, but I want a larger one.

I have found one that might work, but was hoping there would be a bit smaller and cheaper option you may know of.

I've looked around a lot and have found a couple options, but nothing like an enlarged version of the smaller one.

Please let me know if you have any ideas where to find something like this.

Hello everyone, I'm not an expert with electronics but I'm trying to learn this. I have this circuit that requires USB c to charge but the output should be 18v ( portable jet fan ) I've test the output without the batteries and it's only receiving 4v which is the component i have to focus on and how to correctly test it

Put together a power amp and am in process of testing/ making safe and am reading a voltage of almost 10vac between audio ground( centre tap) and earth? Is this a concern? Added an image so you can get an idea of what I’m working with.

Hi, im finishing my simple project - a 3d printed cat lamp that changes color based on the pc's temperature.
i've used arduino nano and some dht22 circuit(?) i do not actually know what purpose this circuit serves as opposed to raw dht22, but thats another topic.
So i'd like to keep my pc as clean as possible, but arduino as well as the sensor circuit have built in diodes, which glow intensive red whenever powered. I'm getting tired of putting horrendous amounts of electrical tape on every diode in my projects. And there comes my question is unsoldering the diode from arduino or the dht22 circuit going to break it's functionality? If yes, then are there any other solutions? I guess for arduino i can somehow do it in the code, but i couldn't find any info about it on google. However i'll keep trying. My biggest concern is the sensor module.
Also, do you have some tips on how to connect multiple wires to single point? Like, i have a few wires that needs connection to common gnd, i always solve it by just creating a big blob of tin and putting every wire into it, but it is also kind of tiring and there has to be a better way...

I'm sorry i couldn't find the schematic for dht22 but that is some completely random circuit that was available with a fast delivery, i'm providing the most detailed photo i found tho. The pins, from left to right are consecutively GND | nothing(nc) | DAT | VCC

this already has a dc input but its so small that it has been wearing down keeps disconnecting. I want to diy a more stable connection by using the battery compartment and connecting a better dc socket or an ac adapter instead Need help figuring out the voltage and the negative/positive terminals. Thanks!

Hi, i'm pretty new to electronics and am wondering if I could use a cheap osciloscope to learn how, why and when to use it? Or is it more worth to just buy a midrange one and learn on that?

I broke the pads 1, 16 and 22. Checking schematics, 1 is suppose to not be connected, and 16 and 22 are connected. But i dont see any connection from this pads at all.

Any advice of where should i wire this chips legs? I read they go to Q8 and Q11, but i cant find it labeled on the board.

I'm looking to replace a resistor that looks to have overheated and disintegrated from the PCB. Per the repair manual, it is a 3.3k ohm SMD with +/- 5% tolerance. Size wise, the solder joints are ~1.2mm end to end (label R4125) which aligns to the length of the other resistors that are part of the circuit (label R4128 is 10k and R4127 is 5.6k.; both are ~1.2mm in length). This makes me believe these are 0402 sized resistor and per the repair manual, I know that these are NOT 1/10W SMDs.

Those are all of my knowns. Looking at DigiKey's filters, I need to guess at the:

• Power (0.0189w to 0.25w)
• Composition (Metal film, thick film, thin film)
• Temperature Coefficient (+/-2ppm to +/-200ppm)
• Features (Anti-sulfur, automotive, military, moisture resistant, pulse withstanding)

How would I go about selecting the values for the above 4 elements? Do any (beyond power) have a meaningful impact on the resistor? The application here would be for a Pioneer DJ CDJ2000 player (I posted some more details yesterday: https://www.reddit.com/r/AskElectronics/comments/1jqu1rz/looking_for_help_confirming_im_troubleshooting_a/). TIA!

I don't know a lot about microcomponents, it may be a diode. No references found for the number.

Just dismount my printer to with the motors, but this board looks funnier what are all this chips and what can i do with this stuff?

Does anybody recognize this connector or maybe knows who makes it? It's used on a flexible induction clamp and it's missing the clips. The manufacturer of the tool can't or won't provide replacement clips and the part is pricey, I'd hate to scrap it just for this. It's likely European, I think it's made in Germany.

Hi everyone,

I run a human rights project in Bangladesh, and I'm looking to build my own RF detector to detect covert surveillance devices, including microphones and cameras that operate over SIM cards (mobile networks), Bluetooth, Wi-Fi, and other common frequencies.

Unfortunately, I couldn't find reliable RF detectors available locally in Bangladesh, and the few that I did find were prohibitively expensive. Importing from abroad is also not an option due to high costs and the bureaucracy involved. So, I’ve decided to build my own RF detector.

I am new to electronics, so I’m seeking guidance on how to get started with this project. My main goal is to build a wide-range RF detector that can detect a broad variety of surveillance devices at a low cost.

My questions are: Can someone link to a beginner-friendly article or guide that explains how to build an RF detector for detecting a variety of bugs, including those transmitting over mobile networks, Bluetooth, Wi-Fi, etc.?

I’m looking for something that’s relatively simple to assemble and cost-effective for a newbie. There are a lot of articles out there, but I’m unsure which one is most appropriate for my needs.

I’d really appreciate any suggestions, resources, or advice you can offer!

Dunno if this right page but seeking advice

Ive got some LED filiments im placing in a project , they say they want 3v DC less then 400ma

Right now ive got em plugged into 2 AAAs which work but i wanna plug into wall , like USB C

But in my efforts to find a board that can use all im finding is 3v battery charging boards

Hoping the pictures are clear enough. I need to replace this part and don't have a clue what it is called.

I searched on the Mouser site and came up empty. Probably because my search term wasn't correct.

Bonus points if anyone has Mouser part number 🤣

Thanks!

I’ve been messing about with piezo buzzers and just generally trying to get my head around some basic bits of bobs with various components that tend to come in a kit… but they all seem to make a kinda nasty whistle sound. Y’know when you turn on something and it plays a little tune of some description? What is going on there? And how to you influence what “tune” it plays? I’m googling/youtubing every phrase I can think of to understand the difference or whether it possible to generate multiple notes from a standard buzzer? Or is it more of a micro-speaker that’s capable of that?

I need help building a PCB, I've been trying to reach myself, but can't grasp it. I'm almost willing to pay someone for their time, so they can create the files needed. I'm wanting to build a pair of headphones, cuz I can't find any that I like. So any help would be grateful.

Would it be worth taking the gamble and purchasing a Ps5 for $70 that is damaged from a short circuit and was "unrepairable" as per a repair shop?

Kids near me are buying musical lollipops, while not rechargeable I think they are fun. Speaker is in the mouth and allow listening to some (pretty bad) music. Is there any way to identify the chip that is used ? Here is what I found : Pin 1 spk- Pin 2 spk+ Pin 3 battery+ through a capacitor ? Pin 4 gnd/battery- through a capacitor Pin 5 gnd/battery Pin 6 led output Pin 7 pushbutton input Pin 8 is connected to a "up" test point

I would say there is 3 music, compressed too much with way too much bass, maybe 1 minute each if it can help.

Just bought and built this pixie cw transceiver, I don't believe I made any mistakes while building it, but it may be the case. When plugged the LED won't turn on and the buzzer does not make any kind of sound, nothing gets hot, nor smoke is released. Can anyone detect any mistake made or suggest anything I can try to fix it? The package included a small pot that does not seem to have any place on the pcb nor is listed on the parts list.

Hi!

I am developing a product that will be utilising I2C protocol for communication with various things like LCD, BMS and more. I just realized that these component have unique address ids and im wondering how that is handled in mass production units when you obviously dont want to update the source code for each device to match the unique ID of the component.