Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [clearance]

Clearance denotes the shortest distance between two conductive parts as measured through the air.

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How do I disable clearance check for a layer or for only some certain elements?

I'm designing a PCB in Altium Designer. There is a very large heat sink in my project. When I put it on the PCB, there will be plenty of empty space under it where I can put other small components. I tried to put some part of this bridge rectifier…
hkBattousai
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Cleaning PCBs... using water?

I found this video where a technician with a lot of experience seems to clean his PCBs using water, and then he just puts it in the sun so it can dry. I was just amazed to see the circuit keeps working as intended, he says he keeps doing this all…
GoatZero
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Clearance rules for outer/inner layers?

I found some information about general creepage and clearance distances here but it doesn't mention what is OK for inner layers, which are insulated and not subject to contamination the way outer layers are. Anyone know of a good reference for…
Jason S
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How to change polygon clearance in Altium

In Altium, when I draw a polygon, it automatically leaves a gap around copper of a different net. However, my Vin net is high voltage, and needs to have a 1mm clearance. Therefore, If I draw a Vin polygon, it needs to leave a 1mm clearance between…
Rocketmagnet
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What is a correct method to measure safe maximum voltage of a PCB?

I have a small (24 x 15 mm) PCB for a custom connector. It is intended for low voltage (< 48 VDC) applications, but I am interested in measuring it in order to provide customers a reasonable maximum voltage rating (de-rated of course). It is a 1.6…
JYelton
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Will a cut or a slot in a PCB change clearance or creepage?

Does a cut or a slot in a printed circuit board increase clearance, creepage or both? Some say it will increase clearance, but I don't think clearance will change because, even with a cut in the PCB, distance over the air will be the same. Thus, a…
Bharav
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What are good values for standard design rules (like clearance, trace width, etc.) in PCB design?

I am working on a project for LED control with MCU and LED drivers. I have an input voltage of 24 V and a DCDC converter to 3.3 V for the MCU. Each LED controller will have an output current of 1 A. I searched all over the Internet and could not…
Urban
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PCB trace clearance in 220V circuit

This is a pcb layout where I am converting 220V rms to a DC voltage (for microcontroller). The pcb has severe size constraints. This is one design I could come up with: Circuit explanation: Consider the encircled portion. Top pad is not connected.…
Whiskeyjack
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Same net overlapping pads ok?

I'd like to keep the option between components with slightly different footprints. In this particular case it's tactile switches with either 6.5mm or 8mm distance between legs. It looks ok to me but I'm not sure if there are any contradictions. Are…
sui
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Maintaining clearances in HV MOSFET footprints

I'm thinking of making a prototype PCB which would use a bridge rectified AC, which will end up with peaks around 350V in my area (+/- some smoothing). It's a through-hole design and the circuit will use a MOSFET, e.g. IRF840 (comments welcome). I'm…
Ivan Voras
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Barrier and slot within reduced area on a PCB

Imagine this situation in a little area of your PCB: According to the worst case and used material, I need a creepage distance = 30mm. According some tables, clearance must be 30mm. First Red banana and black connector will have the same voltage:…
Suvi_Eu
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High Voltage Capacitor Lead Clearance

I am designing a high voltage board, 10,000 VDC. I wish to use a suitably rated capacitor such as the DHR4E4A102K2BB. When I have been studying the IPC-2221 and IEC 61010 standards the conductor clearance should be in the order of 0.00305 mm/volt,…
tomdertech
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How is clearance affected by altitude (air pressure)?

Let's say you have a high-voltage circuit (or any voltage really) and you want to provide appropriate clearance distance for the PCB, connector pins, etc. (Above image from link) There are standards for choosing the correct distances. Some of them…
Bort
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Why does increasing altitude (low air pressure) results in lower resistivity/ breakdown voltage?

I got this question because the creepage and clearance distances need to be adjusted for altitude. The higher the altitude, the higher the distances should be. It seems to me however that the contrary is true. What I mean is that we can tolerate…
HatimB
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TO-277A Package Rated for 1000V

I'm looking at using the following part, S4PM: Datasheet The part has a Vrrm of 1000V. The mounting pad layout shows a separation of 0.81mm between cathode and anode. This is well below IPC2221B clearance for 1000V (should be 2.325mm, for a coated…
CJCJCJ
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