I'm working on a small latch circuit, which I would like to default to OFF when the power is first applied.
When I simulate the following circuit, it works as expected. However, when I build it on perfboard, on power being applied the LED turns on by itself. I can turn the latch off and on correctly from here, but powering itself on has me scratching my head. I assume there's something obvious I'm overlooking
The P fet is an IRF9630, the N fet is a 2N7002
Also, I think the falstad circuit sim has the arrows reversed in its P & N fets
That's a caution when using simulations.
They generally give reasonably accurate results for the circuit models used but those models have "typical" idealized parameters with no tolerances, which are highly unlikely to be the exactly the same as the particular parts used in an actual circuit.
So certain undefined conditions, like which state a bistable circuit takes when power is applied, can be different in the sim as compared to the actual circuit. You must be aware of such situations and add power-on reset circuitry to insure a particular state, if that is important.