I'm totally new to PCB design. I'm struggling with this schematic circuit. I'm trying to design its pcb layout using easyeda Shematic is from lab manual of my university Jijel university I would be glad for any help.
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\$\begingroup\$ Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking. \$\endgroup\$– Community BotCommented Nov 30 at 15:08
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1\$\begingroup\$ Is the problem somehow in the schematis, drawing out the PCB layout, or using a specific program to do these things? \$\endgroup\$– JustmeCommented Nov 30 at 15:23
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1\$\begingroup\$ What step in the process are you stuck at? \$\endgroup\$– winnyCommented Nov 30 at 15:47
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\$\begingroup\$ This circuiit seems more a demonstration that a finished product. it looks like it works mainly by conduction, and it exposes the supply voltage on the touch pads. so it's not the sort of thing I would install permanently anywhere. \$\endgroup\$– Jasen Слава УкраїніCommented Nov 30 at 19:42
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\$\begingroup\$ Yes the problem is in drawing pcb layout im trying using easyeda or sprint layout the symbol of ne555 is different in both and im struggling realizing similar shematic to the one in lab manual this is my first time doing such thing \$\endgroup\$– IShak DzCommented Dec 1 at 16:59
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2 Answers
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It is very common for the schematic symbol for an IC to have the pins arranged differently than on the real part if that would make the schematic "neater", or easier to draw or understand. You, and the PCB layout program, just go by the pin numbers to determine the actual connections.
The PCB program may offer different packages/footprints for a part (such as through-hole or surface mount)- then you have to make sure that the PCB program uses the package that you want.
answered Dec 1 at 17:40
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The traces ought to be close together but with a pattern that allows misalignment of the target like a dual X-X or dual spiral. Sufficient capacitance between is 10 pF with 3pF/mm then a >=100 pF finger pad or more will appear as a shunt switch.
The 555 circuit is simply a set and reset with dual contacts. The capacitance is defined by the Length/gap ratio [pF]but the resistance is necessary.
