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Fiora
@FioraAeterna
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3. velj |
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hey electronics twitter
what's the easiest way to control (not just on/off, but analog control) a ~3.3V LED from my ~3.3V microcontroller, using a ~4V signal.
a transistor doesn't seem to work bc the voltage drop results in emitter voltage being ~3.3V-0.7V=2.6V which is too low
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whitequark
@whitequark
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3. velj |
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can you draw a circuit you have in mind? I'm pretty sure you can use a MOSFET to do this, but to give you a precise answer I'd need to understand it better
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Fiora
@FioraAeterna
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3. velj |
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how exactly do MOSFETs differ from NPN transistors that helps me here
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Fiora
@FioraAeterna
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3. velj |
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James Wu
@analogist_net
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3. velj |
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I think instead of trying to use the emitter / source to drive, you put the LED on the high current rail directly, and drain / collector the other end
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Fiora
@FioraAeterna
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3. velj |
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huh, does that actually change it??? i'll try that
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