Questions tagged [pcb]

PCB is the acronym to Printed Circuit Board. A PCB is a carrier for the circuit's components and their electrical connections.

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Identify number of strings in Philips 14.5W LED PCB

Is it possible by just looking at the attached image whether the LEDs are in a single series circuit, or whether they're configured in series/parallel? The image is not great but I tried to highlight ...
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PCB panel design

I am designing a 4-Layer 0.5mm thickness PCB. The outline is rather small which introduces some problems with panelizing the PCB. As I am a novice regarding these topics I would like to ask for help. ...
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PCB 0402/TQFN pad design

I am currently designing a product which uses 0402 passives and other fine-pitch parts. As the PCB-space required is a major design goal I want to reduce the footprints. High production yield is also ...
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How to implement a Bookbinder PCB design in Altium

I am planning to design a bookbinder with airgap rigid flex PCB using Altium. Based on guidelines from Altium, and various other sources, it is important to have "staggered lengths", to ...
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What momentary switch should I use?

I want a switch that has 2 distinct non-momentary states (say UP and Down) and a momentary state. In both states (...
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2 votes
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Connector identification for Avermedia C875

I have an AverMedia C875 device, I would like to capture an analog output of my VCR with it. The device has a specific connector for such purposes, but I sadly don't have the dongle that originally ...
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Can I replace a PWM IC on a PCB with another PWM IC from the same vendor but having a slightly different part number? [closed]

The PCM is of a power supply unit for a speaker and it has this PWM IC (OB2362). I am not able to find an exact replacement to that chip but found a close match (not sure though): the OB2263. It has ...
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Short inside 2 layer ECU PCB

I am repairing a Delphi MT34 ECU, and after further investigation I came to a problem I couldn't understand or fix. After removing the triple regulator IC and all components in the track, the short is ...
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Is it ok to short data lines of USB-C

USB type C has 2x DP+ and DP- on the connector. When laying out the PCB, is it ok to short each DP+ and DP- together?
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Are there any sample reference RF boards for 15 GHz? [closed]

I'm working on our RF project frequency up-to 15 GHz for our application. We are little concerned about the impedance matching, track width, signal trace routing from top to middle layer, trace ...
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How to remove tenting from specific vias?

I defined a SolderMaskExpansion rule in Altium and with that way all vias are tented. But I want to remove tenting for some of the vias. I mean, I want some vias to be tented and some vias to be non-...
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PCB Routing Considerations for multiple USB Port Types for USB 1.1 Full Speed

I wanted to make a device that has a USB A and a USB C connector on apposing sides of the PCB, similar to the attached image. These USB connectors would be connected to the same USB port, the MCU I ...
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10 votes
6 answers
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How does current flow in multiple vias?

How does current travel in multiple vias from one layer to other? For example, we connect four vias, each of which has a limit of 1.3A each from power plane to sink device. If the sink draws 4A of ...
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2 votes
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PCB etching went wrong or what?

I was trying to etch a PCB of 12x23 cm using FeCl3 powder. Below are the pictures of the process: Before dipping into etching solution (some tracks were corrected using permanent marker): After ...
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Using other boards than PCB for commercial electronics products

If one solders entire circuit components (such as resistors, caps, opamps) a board as in the following photo: Is this type of interfacing legal for commercial products? I'm wondering if there is any ...
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Circuit appeared to work for a few minutes at first, then poof! Can you help me figure it out? Diagram included

thank you for taking the time. I have this PoE design that takes 48V and knocks it down to 5V for powering generic USB devices. I received some new boards and when testing them, discovered they ...
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3 answers
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How would one build a circuit board without hiring a manufacturer?

Assuming one had access to old CPUs, ram, hard drives, and mainboards with I/O connections and BIOS chips and other chips in them. I know the basics of the gates to make CPUs and RAM, and I know it's ...
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Eagle I can not change the isolete value of bottom Ground polygon

well this is my PCB design with Eagle Autodesk. Ground polygon looks perfect with Isolate value 0.8128 [mm] on Top. but this value can not effect bottom polygon Why? How can apply 0.8128 isolate ...
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Different capacitors between VCC and ground required for different sensors and components [duplicate]

I am designing a custom board with a ATmega16u2. In the specifications of the linear voltage regulator, a 10uF capacitor is required between the regulated voltage and ground. A 1uF is required between ...
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3 answers
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Resistance measured individually vs measured on PCB

I always wanted to ask this question. Suppose I have a 1kohm resistor. I measure its resistance by connection a multimeter to both of its terminals (when it is not connected to any part of a circuit.) ...
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Where can I find large thru-hole heatsinks like this? [closed]

I'm doing a project with an OPA541 amplifier, and I need to find a heatsink similar to the one in the pictures: But I only found small ones with a screw hole and legs for soldering, none of the large ...
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5 answers
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Is voltage important for calculating PCB trace width? If not, why?

As per the IPC 2221A the formula for calculating PCB trace width follow the process given below; First, the area is calculated: Area[mils²] = (Current[Amps]/(k*(Temp_Rise[°C])b))^(1/c) Then, the width ...
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1 answer
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Add only a subset of components to PCB in KiCad

In the KiCad PCB Editor, when I click "Update PCB with changes made to schematic", all missing components are added to the PCB. How can I add only a specific selection of components? (For ...
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Using High Power Relays to Actuate an AC Motor

I want to remove the need for contactors in a motor application. Currently we are using a 1.5HP (1.1KW) motor and actuating it via a contactor. I have a PCB I am designing and want to use the ...
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How to deal with one clock input at the IC when most crystals and oscillators have two pins?

I am having trouble in figuring out how to deal with an IC that only has a single input for the sleep clock. Does one pin of the clock go into the IC and the other to ground, or does configuration ...
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Class AB RF Amplifier with only one active device

I'm designing an amplifier for the 420-440MHz band. I'm looking at using the following part from Ampleon: BLP15H9S100. I'm new to doing RF amplifier work and I've been going through the design process ...
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How to fix the keyless key (replace the antenna) of Mistubishi Outlander?

Background story: I had a keyless keyfob for my Outlander, and lost it. I went to the service and they configured a new key for me. The serviceman told me that many times when the key falls the ...
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2 answers
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Is 0.01" dimensional tolerance the industry standard for class II and class III circuit boards?

Or does it vary? This is a reference request for ridged PCB thickness. Email from a US manufacture: This is from the board house. Your customer has a profile (routed pcb outline) tolerance of +/- 0....
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How can I adjust the imported 3d body in Altium designer?

I've downloaded and imported the following SMPS transformer 3d model into Altium designer but it doesn't fit my footprint how can I adjust it by changing scales and moving pins?
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2 votes
1 answer
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Bandpass filter doesn't work when implementing PCB

I have been trying to make a 5th-order Chebyshev filter going from 500 MHz - 570 MHz and a 3rd-order Chebyshev filter going from 500 MHz - 540 MHz. This is my first time making a filter into a PCB. No ...
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PCB and breadboard parasitic capacitance

I am getting different bandwidth measurements from my breadboard and PCB (for the same circuit with exact same component values). The cut-off frequency I measure on the breadboard is slightly higher ...
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Kelvin connections in PCB

in the following webinar from youtube, a recommendation is presented about the kelvin connection at the 41st minute of the video. but I couldn't get it. (second language) https://www.youtube.com/watch?...
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How to unplug these connectors on 80's amp/receiver

I'm trying to unplug these connectors to get access to the lcd display. Do I need a special tool? I tried but to no avail. The little ones seem fragile. What is the name of these connectors?
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Plane layer thermal relief rotation with Altium?

It is straightforward to configure horizontal/vertical thermal relief connections with polygons, but with Plane layers, it seems the option isn't available. The result is not very professional (see ...
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-1 votes
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How to use plane layers with Altium and Eurocircuits?

I don't quite understand Plane layers in Altium. For one particular project, we made a decision to use Plane layers instead of signal layers. When exporting the production files (Gerbers) and ...
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4 votes
4 answers
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Is there any difference between Silicone and RTV

I've used silicone RTV that's intended for use on PCBs and have also used 100% silicone purchased from the hardware store to use on PCBs. I was not able to tell a difference between the two. ...
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1 answer
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Antenna feed trace keep it short or long?

I am designing a GPS module but am quite new to RF design. I have seen a number of people say to keep your antenna feed line as short as possible. But in the design guide of the GPS module I am using, ...
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1 vote
2 answers
115 views

Magnetic field shielding for electronics?

I am looking at an issue where a PCB design that is powered by a couple of CR2032 batteries will shut off all of a sudden in the presence of strong magnetic fields (around 15-40mT). However, when the ...
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What could the component be if the diode test result shows finite voltages for both orientations?

I was trying to identify a 2 terminal component using the diode test in DMM- It measured 0.420V in one direction and 1.88V in other direction. I am not sure what this component could be. For other ...
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High Voltage & Low Voltage PCB Design

I am trying to make a PCB that acts as a "Raspberry PI HAT" and allows me to connect the raspberry to different sensors. Specifically, I'm having difficulties in defining the design rules ...
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2 votes
1 answer
107 views

Greener way to design a PCB

Lets say we are designing a very simple PCB and there is a layer(s) where not much is going on, from an environmental perspective alone would it be better to leave the layer with a large ground copper ...
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What is the use of this capacitor compared to the other near it?

It is a lock PCB circuit and I can't understand why it's parallel to the 12 V and ground (the capacitor I circled), but the other capacitor (C539) is like a maintaining contact for 24 V.
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3 votes
2 answers
363 views

Drawing a very simple component in KiCad without the model

I am designing a PCB in KiCad that includes the 328ST160 and 328SR160 transducer pair. I have been unable to find a PCB symbol for the two. The physical component I have is just two pins, like so: I ...
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2 votes
3 answers
189 views

Placement of a decoupling capacitor

I am using the CD4046, and trying to put a decoupling capacitor on it. However, the power pin is on the literal opposite side of the power pin, like so. As you can see, I have a decoupling capacitor, ...
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0 votes
1 answer
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Wierd noise on GND when I touch a metallic object to it

I am facing a problem. I have a PCB designed which fails ESD tests. The PCB is powered by an external power supply that provides 12V to the system (from 240V AC.) The power supply is CE certified and ...
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Should I make these rectangular PCB cutouts larger to account for corner radius?

I am designing a PCB to fit one of these SCART connectors. The recommended PCB layout for the connector includes two rectangular cutouts, each 3.0 x 4.5 mm - these are designed to accommodate brackets ...
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1 vote
1 answer
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Stepper motor doesn't move, just vibrates using DRV8428

This is my first time trying to create a stepper motor driver with my own PCB so apologies if I've missed something super obvious. Anyways, I'm trying to use a DRV8428 (datasheet) to move a stepper ...
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Audio noise on output of PCM1789

I am developing a Bluetooth adapter to be able to listen to music from my phone in my car. I am doing that with ESP32, from which the audio data is sent to PCM1789 which converts it to the analog ...
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1 vote
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Could we connect one crystal capacitor to power and another to ground?

There is a 12MHz HC49 package crystal which according to TLV320AIC23B needs two 22pF capacitors to ground. In the picture below, I can't connect both crystal pins by capaitor to ground. I can connect ...
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1 vote
1 answer
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Why would this PCB design cause a short?

Yesterday, I designed my first ever PCB. It's meant to take data from several sensors and pass the data to a Raspberry Pi, which will in turn actuate pumps to control nutrient concentrations in a ...
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