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Beginners / Re: XOR gate problem with GND
« Last post by Ian.M on Today at 11:04:39 pm »Certainly that's another way of implementing an XNOR which is all you need if the load is active low.
Recent Posts
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Manufacturing & Assembly / Source for small "potting boxes"??.....
« Last post by Smokey on Today at 11:04:30 pm »I'm looking for a good source of small potting boxes. The kind you put your PCB in and then fill with epoxy to act as both a weather seal and a housing.
Requirements include some sort of mounting tab to screw the thing down.
Here is an example of the configuration I'm looking for at the moment:
I would think someone would have that off the shelf. I don't really want to have that custom made right now.
Thoughts?
Requirements include some sort of mounting tab to screw the thing down.
Here is an example of the configuration I'm looking for at the moment:
I would think someone would have that off the shelf. I don't really want to have that custom made right now.
Thoughts?
3
Projects, Designs, and Technical Stuff / Re: Webench Help - 5V buck mode supply
« Last post by davegravy on Today at 11:02:59 pm »My average current draw will be ~150mA @ 5V, whereas 0.7A is my max draw (during very low duty-cycle Rx/Tx)
I looked at the RT6224D for example, efficiency at 12V input at 150mA is only 85% whereas Webench's solution claims 97.5%
I looked at the RT6224D for example, efficiency at 12V input at 150mA is only 85% whereas Webench's solution claims 97.5%
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RF, Microwave, Ham Radio / Re: WSJT-X on Pi
« Last post by metrologist on Today at 10:58:20 pm »Many years ago, with a Win98 laptop, I could interface with my HF rig using PSK31. I can't do that now with the latest computing tech.
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Repair / Re: Desoldering advice
« Last post by modoran on Today at 10:57:02 pm »Use a preheater or hot air simultaneously to get the whole board arena to at least 80C and the relay will be desoldered much easier.
No smd part will fell off even at 230C due to the surface tension. But however aluminium caps will not withstand that .
No smd part will fell off even at 230C due to the surface tension. But however aluminium caps will not withstand that .
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Repair / Re: Rivets/eyelets for PCB repair
« Last post by mightyohm on Today at 10:55:28 pm »lots of choices
https://au.rs-online.com/web/c/esd-control-cleanroom-pcb-prototyping/pcb-tools/pcb-rivets-riveting-tools/?sra=p
I'm not seeing assortments here - it looks like the min order for the smaller (eg. 0.4mm ID) rivets is 1000 pcs, so that's $98 per size plus the tool!
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Repair / Re: Rivets/eyelets for PCB repair
« Last post by mightyohm on Today at 10:51:58 pm »Just drill a smaller hole and use a piece of wire. Cut flush. Works great, and it's hard to beat the price. Attached is a poor picture of a couple of projects. Both sides of the board are shown.
I've done this before. Several years ago I had access to an LPKF PCB mill and resorted to doing this in order to make double-sided boards.
However, the wire method doesn't work for my present use case, which is repairing damaged plated through holes in 2-sided PCBs. I need to be able to insert a component lead through the hole.
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Repair / Re: Motherboard has no power - Clevo W650SC
« Last post by modoran on Today at 10:51:38 pm »Then use IPA to see what is getting hot. Is not as fast as a thermal camera, but it will din the job.
Inject 1V and a lot of amps into the circuit.
Inject 1V and a lot of amps into the circuit.
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RF, Microwave, Ham Radio / Re: RF Test Automation
« Last post by vino on Today at 10:47:57 pm »These are the parameters that I'm interested in automated testing.
1. Gain
2. Gain Flatness
3. IMD
4. Psat
5.P1dB
6. Spurious
I know how to test them manually and I'm also confident in using the equipment and tools to test them.
I just want to take advantage of capability of the programming language such as Python to make my work easier. By incorporating test automation.
1. Gain
2. Gain Flatness
3. IMD
4. Psat
5.P1dB
6. Spurious
I know how to test them manually and I'm also confident in using the equipment and tools to test them.
I just want to take advantage of capability of the programming language such as Python to make my work easier. By incorporating test automation.
10
Beginners / 555 driver and Transformer questions
« Last post by DanMann on Today at 10:47:40 pm »I apologize if this is the wrong section, I am having trouble searching for answers as I think I am unable use the correct words to explain for a search query..
Do the traditional transformers need to work at specific frequencies? A hypothetical, I have a radio shack transformer on my bench that is primary 120V 60Hz with an output of 12.6- 0 -12.6.
If I put a lower frequency the transformer gets noisy, which seems like trouble. However would running say 180Hz to about 1KHz have any ill effect on the transformer.?
In trying to make a 555 astable driver to a mosfet to cycle a (different) transformer at 180Hz from a 6 volt battery.
In using online calculators I have been playing with combinations of resistors and capacitor and see that I can get 180Hz in many ways, but the time high and time low vary.
Is there a ideal combination ratio of the high and low time?
Do the traditional transformers need to work at specific frequencies? A hypothetical, I have a radio shack transformer on my bench that is primary 120V 60Hz with an output of 12.6- 0 -12.6.
If I put a lower frequency the transformer gets noisy, which seems like trouble. However would running say 180Hz to about 1KHz have any ill effect on the transformer.?
In trying to make a 555 astable driver to a mosfet to cycle a (different) transformer at 180Hz from a 6 volt battery.
In using online calculators I have been playing with combinations of resistors and capacitor and see that I can get 180Hz in many ways, but the time high and time low vary.
Is there a ideal combination ratio of the high and low time?