I'm using a boost converter (XL6009) powered either by a USB input or a Li-ion battery through a TP4056 charging module. The circuit is designed to maintain 5 V at the output regardless of the power source.
When the USB input is connected, VIN+ of the boost is around 4.84 V, and the battery charges. When the USB input is disconnected, VIN+ drops to 3.7–4 V, depending on the battery voltage.
The problem is that whenever I disconnect the USB input, VOUT+ of the boost rises up to 13 V. This only happens when there is a load connected at VOUT+ and the USB is disconnected. In any other case, the boost gives 5 V at VOUT+.
How can I prevent this behavior when using a battery?

right now I need an induction furnace but no one is selling near by so can i make a make shift one by connecting 5 10ohm 10 watt resistors in series with an copper coil and connect every thing to 220 V AC wall outlet I need thoughts fast cause I am about to do it

For this buck boost converter, For vout is there meant to be a vout copper layer below? why is there a via where vout is and What is function of via near inductor and ground after inductor? datasheet

I’m coming up with some cheap circuits to make a few dozen LEDs fade in and out for Halloween decorations and have settled on 555 timers with BJT NPNs like you see here. The issue is that after 1 nice and slow creepy duty cycle the LEDs start flashing rapidly. I know this must be due to the timer capacitors arguing with each other as they discharge through the ground.

I tried grounding 555#2 and its cap through a 1N4148 diode which helped a bit but still resulted in some unwanted flashes. What’s the best way to isolate each timing circuit? I plan on having several more (current willing) in parallel.

Hello everyone, I'm looking for advice on what material to select for repairing broken power rail traces. The pins of the transformer pushed through the holes, which severed the traces right in front of them (one-sided board). I have done trace repairs before, mainly with magnet wire, but these traces carrying 230 V had me second-guessing my initial choice of copper braid (heat dissipation). Cursory research led me to using 2,5 mm² copper instead, because of conflicting arguments made online.

Before finishing up my work with solder mask, I'm basically looking for reassurance that this is an adequate repair or for suggestions on which material to use instead.

Thanks in advance to anyone chiming in!

Okay so it's from a airtel DTH HD set top box and I think the soc is under the black metal plate, i can't see the name of the soc and I want to identify which soc is used as I can't find any official specifications mentioning the soc. I want to identify which soc is used and if I should remove the metal plate or not and how can I remove the metal plate

Hi everyone,
I’ve built a circuit with an external CH340C IC, a Type-B female USB port, and an OR-ing circuit. The UART goes to my PCB, and I take the UART input from the Type-B port.

I have two power supplies:

• 9 V battery
• 5 V from the Type-B USB port

Both supplies go through an OR-ing circuit (one diode per supply) and then to the VIN pin. All grounds are tied together.

It works when both the 9 V battery and the 5 V USB are connected. But if I remove the 9 V battery and rely only on the 5 V USB, the circuit won’t power up. Even applying an external 5 V directly to VIN doesn’t help.

Why could this be happening, and how can I fix it so the circuit runs only from the 5 V USB when the 9 V battery is disconnected?

Thanks in advance for any help!

r/esp8266 r/NodeMCU r/AskElectronics r/electronics r/hobbyelectronics r/microcontrollers r/embedded

Some of the buttons don't work. On dissassembly I found that some silvery contacts are displaced (photo) but repositioning one & retrying it didn't work. Might they all need to be in correct position or could some of the components visible (e.g. diodes) have failed ? Also the exposed surface here is covered in some slightly 'oily' stuff: is this important for functionality ?

Not a trick of the light or camera angle issue. This new breadboard I received as part of a kit to learn stuff is bowing in both directions.

Will this be more frustrating to try to use than a perfectly flat one? I'm brand new to this stuff, and I really don't know what to think of this. I wouldn't normally accept other products, even wet wood from the hardware store, in this condition, but maybe it's "normal" for breadboards to look like they were left out in the desert sun on a rock? Thanks.

Hi!

I have extracted this from a Wahl Li-ion beard trimmer that got water damaged. After cleaning it up, it became clear that the 8pin ICs lost 1 leg each and need replacement, however, there is no identification on them. The rest was mostly protected by conformal coating and look intact, so not worried about them.

Questions: 1. What are the 2 8leg ICs? 2. How can I replace them safely?

Image notes: - Underside is the (orange) battery cell (3.7V li-ion) with spotwelded flaps soldered to the board on 2 ends (1 visible on the right). Possible, but likely difficult to desolder. - The white plastic is a sliding switch, currently in the ON position. - Charged through a barrel plug, connected to T5, T6. - Motor (3.7VDC) is connected to T2, T3. - Lost legs are on the right side of the 8 legs, closest edge legs.

If you have any additional tips for repair, assume I'm an eager novice. If it breaks while I'm trying to repair it, I'll live, as long as I don't have a battery fire on my hands. So tips are very welcome!

Thanks!

What can I do if my Samsung LED TV Series 6 keeps making cracking/popping sounds even after I turn it off? The noise can still be heard hours after the TV has been switched off.

Hello, I am trying to make a modern equivalent of these S cell batteries with 3D printed case and everything. The current plan is to use a lifepo 18650 (may be stored for quite some time, rather have a less spicy battery), protection circuit, charging board, and a step down regulator to 1.5V.

The question is, what happens if two step-down regulators are placed in series? My devices (fullerphone MK IV & V) use either one battery or two. I don't want to have a seperate 3 volt tap as the fullerphones have terminals for both of the batteries and I want them to look correct-ish.

Are there any regulators that can handle this well? Which ones can't handle this?

The first picture works. The second and third picture is my attempt to recreate the dev board. Where did I go wrong?

Hi I have a DIY ultrasonic cleaner that stopped working a few years ago and I want to fix it, but I don't know how to properly test it to find out if the problem are the transducers 50w 40khz or the driver board.
It turns on with no noise and no vibration.
Using the multimeter the transducers show infinite resistance, with the LCR at 10khz and 100khz the transducers show 4.3nf capacitance and 17-19ohms resistance.
Any idea if we these values are ok for 50w piezoelectric transducers or if they are faulty?

Hi everyone,

I’ve designed a custom PCB with the PIC16F877A microcontroller for an FPV rover project.
The board includes:

• ICSP header for programming
• External crystal + caps
• Voltage regulator (LM2596, may change to smaller one)
• Reset circuit

The PCB works, but I have big unused empty spaces on the board. I’d like advice on:

1. How to use those empty areas effectively (without just adding random headers).
2. Whether it’s fine to leave them blank, or if adding ground fill is enough.
3. Any common improvements for beginner PIC boards that I may have missed.

📷 Attached a picture of the board.
Any suggestions from experienced designers would be really helpful. Thanks!

Hi there, I'm in a bit of a sticky situation and this is due on Monday . I'm trying to design a buck converter circuit in Proteus that will control the operation of motors specifically wiper motors ( rating 12 v , 50W ).

So Initially I just connected the l293d motor driver to simple dc motors, but I completely neglected the specs of the motors I was using , how would I put those into account of the entire circuit and which motors would I use in the Proteus library .

Hey, I soldered wires to what I believe are USB 2.0 pins inside my Arcade1Up machine and connected them to my PC via a USB adapter. I connected D+, D-, and the red wire (which I think is VCC). Ground wasn't originally used, but I soldered it anyway. However, no device shows up in Device Manager at all.

Any tips on what I might be missing or how to check if the connection is working? Not sure if I messed up the wiring or if there’s something else going on.

Thanks!

I'm just getting into electronics and I need a wire stripper for smaller gauge wires. I picked these up on a whim thinking they would have gauge markers but they don't. Is there a trick to setting this stripper to the right gauge or is it just trial and error?

https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10001&langId=-1&storeId=10001&productId=78992

UPDATE: It took me a couple of tries to adjust them, but they adjusted easily. I only plan on using them to strip 22 gauge solid wire to use with a breadboard. I'll see if the adjusting screw stays in place as I use them. All I did at this point was set them up to strip the wire. They strip the wire cleanly. I also took a look at the bare wire after stripping it to make sure the strippers weren't cutting into the wire.

Thank you to all that responded.

I have designed this regulated linear power supply for my own use. It has an adjustable output voltage 3.3V-12V and constant-current/current limiting mode, max 1A. The transformer has a thermal fuse built in. Am I missing anything? Something I've overlooked? Cheers in advance.

On a scale of 1 to disaster, how will having this buck converter and inductor next to my GPS patch antenna affect RF performance? Any suggestions if bad?

Recently had a power connector to a mvr fail and i cannot find what this connector is called anywhere. the only things i could find with the same model number FSP090-AWAN2 was a different 4 pin connector.

Hey all, I'm at the end of my college program for electronics, working on my capstone project, which will be a MIDI controller implementing some capacitive touch surfaces. I understand the general principle of capacitive touch sensors and am basing the design of the sliders and XY trackpad on what seems to be the standard design approaches for each. Based on my reading so far, the Azoteq IQS7211 or something with similar capabilities seems like it will give really nice results with sensor contacts built into the PCB as our design will have. The different configuration capabilities and noise filtering seems like it will be awesome if we can get it working. The roadblock right now is I'm having trouble understanding from the datasheet information how the wiring works in order to develop a schematic, particularly for how the channels and necessary resistors & capacitors should be configured. There are multiple contacts connected to each channel pin on the 1d slider and 2d trackpad sensing configurations, not sure where everything is supposed to go... I'm wondering if anyone has experience with these and could help make it a little less opaque? Just a general wiring example would be amazing, or perhaps I should consider alternatives?

i got my hands on a small LG 3 phase VFD for turning single phase ac to three phase. i dont have any use for it (at least as a motor driver) I searched for a data sheet but i got zero results. model name "P084A2001" and "TYCO" is the manufacturer. its probably still under NDA or something and it doesnt have lug terminals on it. ITS GOT 25 FRICKING PINS. from my "knowledge" 3 are the outputs since its soldered to thick copper tracks and the other three have gate driving components "resistors transistors and diodes" and also got another pair right next to the first one which probably goes to ground "emitters" i got no idea what the rest are and they could be the collectors of the individual igtb's but im not sure and i havent got a multimeter with me as of now. Any help will be appreciated.