Hi and thank your for your response.you were right. One trace between the transistors was not correct. I attached the updated schematic. So this makes more sense since R1 acts as a pullup and can be pulled down via the NPN.So can you use a NPN like this? HY3C.
[...] I'm assuming you got that "HY3C" number off the part [...] If your multimeter has a Diode Tester setting, try using it across the leads on that "transistor".[...]
Yes thats the number of the part labeling. So I tested the part with my multimeter like you said....So how do I interpret this data?
MY quick research with Google shows the SOT-23, HY3C is a Richtek voltage detector, model RT9818C-12PV. There is a PDF available to explain all the details.Paul
But, based on your Diode Tester readings, it does appear to be an NPN. And, judging by the pinout of a '3904 SOT23 package [a fairly standard arrangement], the odds are good that you have the pins marked correctly -- BUT, there is still the chance this is a non-standard part, and the Base-Emitter/Collector-Base junctions may be opposite of typical. And, the only way to sort it out is probably to draw the schematic and see if it makes sense -- which is the technique you've already employed. So, did the Diode test results alter the "schematic strawman"? And, if so, and if you are still unable to evaluate its efficacy -- then, perhaps, present it to us, here, and let's have another look.[/i]
Yes thats the number of the part labeling. So I tested the part with my multimeter like you said.I am assuming this pin layout:
Hi,i got two of theese boards which automatically turn on an IR-LED if the environment is dark (and off if its bright).I want to be able to manually overwrite the status of the LED
Hi,I think this is what you are trying to get drawn;Tom...