u/Giganticsquid3

Image 1 — Help with dual NE555 circuit
Image 2 — Help with dual NE555 circuit
Image 3 — Help with dual NE555 circuit
Image 4 — Help with dual NE555 circuit
Image 5 — Help with dual NE555 circuit
Image 6 — Help with dual NE555 circuit

Help with dual NE555 circuit

Hello, I am relatively new to circuitry so apologies if any of my mistakes are simple or blatantly obvious. I’m trying to build a timed rocket ignition system that after a button press will use two 555s to start a 64 second countdown to then power a MOSFET for 4 seconds and then turn off. The system is run off a 9v but the mosfet will be controlling a different battery(9v for testing but will be a different battery in practice). Long story short the circuit doesn’t work, I have the multimeter hooked to the drain and source but it never reads anything. All of the capacitors are facing the right way to my knowledge and there are pull-ups and pull downs so nothing should be floating. Is there something wrong with the circuit I have designed or is it an issue with my wiring? Also apologies for the mess on the breadboard, I was planning on making everything neat after I was sure it works. Thank you, please ask any questions you may have.

u/Giganticsquid3 — 2 days ago

PN2222 instead of actual MOSFET?

Hello, I am currently building my first flight computer, I know MOSFETs are best for igniting the ejection charge, I don’t have a MOSFET but I do have a PN2222 transistor, will this work? I will be running 600ma at 9 volts through it which is within the max rating of the transistor. Should I just go buy a MOSFET? If so, are there any models you would recommend? The power source for the ignition is separate than the power source for the flight computer. Thank you.

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u/Giganticsquid3 — 14 days ago