DuPont connectors equates to logic level signals. There may even be a 3.3 v <>5v link selector on the adapter.
Whereas DB9 equates to "RS232" level signals. Generally, at least the capability to accept those voltage levels, even if not necessarily producing them.
My first step tends to be to connect tx to rx and see if characters typed in a terminal/emulator get echoed.
An RS232 breakout box is pretty much a given necessity, when it comes to sorting out what's happening on all those pins and sorting out what to connect to what.
Thank you for the reply. The one we have on hand has 4 pins. An exact replacement would be great, but at this point if we can just get one to work, that'd be fine as well. I appreciate the help! I'll dig around and see if I can track down datasheets to review.
Since writing this though I realised something important I had forgotten - these are rechargeable cells. And if they are wired in series, it means I need a much more complicated charging circuit (I currently use TP4056 boards to charge cells).
So even though series might be more efficient, I think I'll need to use parallel as a single TP4056 can charge two cells in parallel.
Funnily enough I have exactly the same set up on my healing bench right now, and was wondering about the same thing. Thanks for posting the question and your realization.
In general, what I remember from step up converters, is that they work more efficient the less they have to step-up. So a conversion from 4 to 12V is less efficient than a conversion from 8 to 12V.
But I also remember that after a certain input voltage the change in efficiency is only minimal. According to the datasheet of the MT3608 this seems to be around 4V.
Therefore I’d connect them in series, but I’m looking forward to other peoples input on this.
Searching for the number hasn't gotten me anywhere neither has searching by the dimensions of the jack. Would like to avoid stealing parts off other systems but as a last resort would consider it.
The standard countryside yokel reply when asked for directions applies, " Arrh, If you need to get to there, I wouldn't be starting from here".
For battery powered LED lighting - you shouldn't be using 12v LED strips. You should be using bare LEDs and a constant current supply. Converting cell voltage to 12v, only to use (probably) resistors to limit LED current isn't the way to go.
You will lose far more, efficiency wise, starting from there, than you are worrying about losing in the series or parallel considerations.
But then, you'd design the required power source and then the charger associated with it - not start with a charger, which then constrains your battery pack topology.
As the other commentor said, ebay is a good place to look for such things but don’t search the part numbers. Search the model number of your device. Get the model number as specific as possible. Sometimes there’ll be a model number printed on the outside or on the box it came in, and that number is like a customer facing model number with a different model number that the manufacturer goes by. Like you’ll have a Samsung Note 8 and that sounds like the model, right? But in reality, it’s a SM-428Z-J12 or something. That’s the model number you want to search. Do some research on your device to get the right one.
Thanks for your help! Looks almost identical, but not exactly! The little plastic tabs on the edge are a bit further apart on the connector you send me. Or at least that's what it looks like on pictures I find:
Here the little plastic tabs are roughly above pin 1 and 5, on my connector it's more above pin 2 and 4... Hope you can understand what I mean. Any idea?
That seems to be it! Or "JST-PH"? Not sure what the difference is between PH and PHR-5. 2mm pitch seems to be it at least, and plastic tabs seem to be at the right place:
As far as I know are the “PHR” series connectors a variant of the “PH” connectors. They also have a 2.0 mm pitch, but they differ slightly in their housing design. The primary difference in the “PHR” connectors is the presence of a latching feature on the housing. This latch helps to secure the connector halves together, providing additional stability and preventing accidental disconnections.
If you are completely new I suggest watching a tutorial. Otherwise some basic tips could be
if oscilloscope has multiple channels, make sure the channel you connected is the channel nel you see on the screen
make sure you did the ground connection. You need to connect both signal and ground tips if the probe
make sure voltage range is fine. If you use a large range in the screen, little amplitude you got may seem like a flat line.
calibrate your probe, if oscilloscope has that option. But an uncalibrated probe doesn’t explain flat line, it would explain distorted square wave, for example.
Use another probe. They can get broken. If it is broken all you will see will be the noise the cable pics up like an antenna.
separate the issue. Connect probe ends to a battery with k own voltage and see what you receive. If it doesn’t work, you know either probe or oscilloscope is wrong.
List can get longer really, but I think a tutorial and these can go a long way for the beginning.
Can you read what u1 and q1 are in the first image? Q1 looks like a transistor switch and u1 might be a counter. It may be counting a clock or it might be a comparator checking whether a capacitor is charged or discharged to check time. Is there any components on the other side of the board? I would expect a capacitor or oscillator at least for timing.
First image: U1 says HZ300 0053, and Q1 says 3400A. There’s nothing on the back of the board. The second image has two U1 components: the smaller says RCAKL9 00765, the larger is 6228A 2121/33, and the Q1 is 3400X.
For the first one: Would be good to know what U1 is exactly. Can you read any number/code on it?
If you are lucky it is simply a ‘switch’ which switches on once you press the button and switches of after 30min. In this case you could add a wire which constantly switches the lights on. Then add a normal mechanical switch to the power supply cables.
If you are unlucky, U1 also regulates the current through the LEDs. Then cannot be easily replaced. Is there anything on the other side?
First image: U1 says HZ300 0053, and Q1 says 3400A. The second image has two U1 components: the smaller says RCAKL9 00765, the larger is 6228A 2121/33, and the Q1 is 3400X. There’s nothing on the back of the board.
Yes you can absolutely breadboard it. Forcing a current is as easy as following ohm’s law. Make sure there is a certain voltage across a resistor and ensure that only a negligible amount of that current is leaked elsewhere. A difference amplifier is a good way to ensure this, as long as you pay attention to the amplifier input currents.
If current regulation isn’t super important, a highish voltage (say 24+ V) and a large resistor will also work because the variation of threshold voltage will be so small that the voltage across the resistor will be relatively stable.
I think there is some confusion about the word diode here. The transistor is effectively an inverting amplifier, that is that the drain voltage is reduced if the gate voltage is increased. By tying them together, they reach a stable configuration where the gate is just high enough to make the drain low enough for them to be equal. In this configuration, there are two terminals, hence the di in diode. Like a traditional diode, it has a very nonlinear voltage-current relationship. If you apply 10V to it, theoretically the current would be thousands of amperes. Practically that won’t happen but you will blow up the transistor.
I don’t know enough about radiation and semiconductor physics to answer your other questions but if I were you I would just build it and test it. MOSFETs and resistors are cheap and if you do have a radiating source on hand it might be easier to try and fail than to hope someone here can tell you what your part will do when exposed to conditions outside of the manufacturer recommendations.
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