Linked Questions

30
votes
2answers
17k views

Why route air gaps for voltage isolation on PCBs?

Learning about PCB design for power supplies, I frequently see boards with routed gaps to separate low and high voltage sections of the layout. Why go to the trouble of routing an air gap when ...
8
votes
6answers
8k views

PIC16F628A Resetting after relay turned off

I am having problems with controlling a relay with load on it. I am using PIC16F628A. The problem is following: The relay has load. At first it is off. When the microcontroller's output is on, the ...
11
votes
7answers
5k views

Mains Voltage on Strip Board

I need to prototype something quickly as a proof of concept. Is it safe to use mains (UK 230V) on stripboard? It will be going to a transformer so I can control some appliance. Or should I design a ...
14
votes
3answers
9k views

High Voltage PCB Design

I want to design a 4 layer PCB with the following voltage levels. GND, 5V, 3.3V and 80V. In the circuit there are some MOSFETs which are driven by 3.3V and MOSFET switch 80V (required current is very ...
12
votes
2answers
4k views

Why AC points on PCB are separated by a hole

I want to find out why, in professional PCB's, they separate between the AC (220 VAC) points on the PCB with a hole in the PCB: Is it for more isolation between the AC lines? Is leaving a distance ...
9
votes
1answer
1k views

Why are there slots around the transformers in this PCB?

I took apart an office printer a while back and this is a photo of one of the power delivery PCBs: (Please note I have removed some components from the PCB). What is the reason for the slots in the ...
5
votes
2answers
3k views

High Voltage PCB

I am building a test probe PCB to test 75-115V. What is the minimum distance between traces that I should adhere to when building my PCB? I will have ground, 3v and 115V traces running next to each ...
5
votes
1answer
2k views

How should I isolate AC and DC on a small PCB?

I am designing a small PCB (1"x1") and it will have some DC logic traces (5V and GND) and some high frequency AC power traces (100V 1000Hz 50mA). Are there any special considerations I need to take ...
1
vote
0answers
575 views

PCB isolation strength VS pad-to-pad distance

Is there any estimation regarding the relation between PCB pad to pad distance and isolation strength? If the board is covered with the mask and the minimum distance is 2,9 mm which isolation voltage ...
3
votes
1answer
263 views

TRIAC with AC plug

I would like to do a small project where I could control an AC PLUGusing a digital signal. To do that, I would need to attach a TRIAC circuit into the AC plug. All it has inside is a fuse so this part ...
0
votes
1answer
129 views

How unsafe is it to use a 10 amp fuse with a trace designed for 4 amps?

Obviously I am a hobbyist and yes I am messing with mains. I do understand the danger which is why I'm asking this question. I originally wanted to make a PCB that can handle 10 amps but I couldn't ...
2
votes
0answers
211 views

Becoming crazy with EU LVD regulation in PCB and electric strength

First of all I will explain the design characteristics of my project to make clear what it is and where it enters for regulation. It is a fixed electric/electronic installation in offices so it can'...