I've built this circuit with soft-latching on and off buttons, and I have two main questions:
https://www.falstad.com/circuit/cir...AADIGgCCABEN9rylW6RP99wAIoAVQAogBlAAqAEknYwgA
The circuit is meant to one that latches on when the 'on' momentary switch is pressed, and which would then power a microcontroller. The microcontroller would be able to turn the power off when it has finished its work. For now, I have modelled the microcontroller as a simple LED with resistor, and I have modelled the off signal with another momentary switch.
The momentary switches should work interactively in the linked version.
Question 1 is:
In the simulation, the circuit is initially 'off'. But when in real life when I built the circuit on breadboard, it seems to start in an 'on' state. Is there a modification I can/should make to have it start in an 'off' state? I already pull the base of the PNP up to vcc which I thought should do the trick.
The on/off buttons do work as expected, which is enough for my use case. I'm just curious/interested.
Question 2 is:
If the 'on' momentary switch is pressed and held down, I can see that current passes through the base of the NPN transistor and out of the collector. I have marked this on my circuit with the label 'QUESTION'.
Is this bad? I could stop this from happening by replacing that labelled wire with a diode, but my question is whether that's something that I should do, or is it okay to leave it as it is?
It might be useful to point out that I'm just a beginner.
Thanks
https://www.falstad.com/circuit/cir...AADIGgCCABEN9rylW6RP99wAIoAVQAogBlAAqAEknYwgA
The circuit is meant to one that latches on when the 'on' momentary switch is pressed, and which would then power a microcontroller. The microcontroller would be able to turn the power off when it has finished its work. For now, I have modelled the microcontroller as a simple LED with resistor, and I have modelled the off signal with another momentary switch.
The momentary switches should work interactively in the linked version.
Question 1 is:
In the simulation, the circuit is initially 'off'. But when in real life when I built the circuit on breadboard, it seems to start in an 'on' state. Is there a modification I can/should make to have it start in an 'off' state? I already pull the base of the PNP up to vcc which I thought should do the trick.
The on/off buttons do work as expected, which is enough for my use case. I'm just curious/interested.
Question 2 is:
If the 'on' momentary switch is pressed and held down, I can see that current passes through the base of the NPN transistor and out of the collector. I have marked this on my circuit with the label 'QUESTION'.
Is this bad? I could stop this from happening by replacing that labelled wire with a diode, but my question is whether that's something that I should do, or is it okay to leave it as it is?
It might be useful to point out that I'm just a beginner.
Thanks
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