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I have a problem with perfboard, every time I made a circuit which works flawlessly in breadboard, doesn't work on perfboard. Is it because of soldering distance or am I doing something wrong?

All circuits are 5-12V and low current (200mA max). First one is 7 segment display, second one pwm motor control, last one Ne555 frequency generator. Display circuit's problem is display randomly flickers segment. PWM's problem is MOSFET randomly opening or closing (and heats up). NE555 problem is output is always on even NE555 removed.

It seems like solder or perfboard causing the voltage jump (somehow) but I checked several times and multimeter shows no connectivity, I tried to clean the paste and clean the space between solders but still no luck. Some of my circuits to show the problem:

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    \$\begingroup\$ You're probably just making errors when assembling. I find my chances of getting a PCB to work properly are always much lower on a protoboard when I'm basically wiring "on-the-fly" than on a custom PCB. There's just way more that can go wrong. \$\endgroup\$ – DKNguyen Oct 18 '19 at 21:54
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    \$\begingroup\$ Those are some neat, but large soldering bridges. You might consider using less solder and smaller gauge wiring to connect things. That would reduce the chance of having unintentional bridges. \$\endgroup\$ – JYelton Oct 18 '19 at 22:00
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    \$\begingroup\$ Switch to stripboard such as Veroboard. See my answer to electronics.stackexchange.com/questions/395053/…. That way you only need a quick solder spot on each component leg or pin. \$\endgroup\$ – Transistor Oct 18 '19 at 22:00
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    \$\begingroup\$ They don't really have exact names. Veroboard is more of a brand name. Stripboard has copper trips. I consider perfboard (perforated board) to just have holes and not even copper pads, but some people might include copper pads. Perfboard definitely doesn't have connections between holes. I call a protoboard (prototyping board) anything generic board that you solder that isn't a custom PCB. \$\endgroup\$ – DKNguyen Oct 18 '19 at 22:09
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    \$\begingroup\$ Related, maybe helpful: electronics.stackexchange.com/q/2215/2028, electronics.stackexchange.com/q/176233/2028, and electronics.stackexchange.com/q/55236/2028 \$\endgroup\$ – JYelton Oct 18 '19 at 22:10