Automated Power Cycle

Started by ABLE1 in sci.electronics.basics2 weeks ago 3 replies

Hey all, Has anyone used or installed a 120volt power relay that would allow for a 23 hour 59 minute on time and a 1 minute off time that...

Hey all, Has anyone used or installed a 120volt power relay that would allow for a 23 hour 59 minute on time and a 1 minute off time that would then repeat the cycle?? The desire would be to have a remote device do a daily reboot without human intervention. I know I can build one to do the job but I was wondering if someone knows of a device that would be off the shelf available to ju...


Non-thermal microwave injuries

Started by bob prohaska in sci.electronics.basics3 weeks ago 3 replies

When the first reports of diplomats at the American Havana Embassy falling ill were caused by microwave injuries it seemd quite implausible. Now...

When the first reports of diplomats at the American Havana Embassy falling ill were caused by microwave injuries it seemd quite implausible. Now it seems more incidents have emerged, and the Frey effect, discovered in the early 1960's, at least indirectly supports the idea microwaves can have lasting non- thermal effects on humans. The article is at https://www.nytimes.com/2020/10/19/us/polit...


Help required with 22V10 - Using a pin as Input an Output

Started by Dave Hitchins in sci.electronics.basics3 weeks ago 1 reply

I'm having problems with the SDA part of an IIC implementation in a AMD 22V= 10C (not from China!). I can Output data, to the SDA output, but I'm...

I'm having problems with the SDA part of an IIC implementation in a AMD 22V= 10C (not from China!). I can Output data, to the SDA output, but I'm not ab= le to read the SDA input! My CUPL equations, as a whole, compile OK using W= INCUPL and the .JED file programs OK. These are the intermediate declarations: FCD7=C2=A0=C2=A0=3D !nPFC & A7 & A6 & !A5 & A4 & !A3 & A2 & A1 & A0; SCLH=C2=A0...


? on old electrolytic caps

Started by Dave in sci.electronics.basics1 month ago 23 replies

I have an LCR meter which shows the ESR for electrolytic caps, but I have no idea how to interpret this number. How do you know if a cap is...

I have an LCR meter which shows the ESR for electrolytic caps, but I have no idea how to interpret this number. How do you know if a cap is shorted or boardering on that status? I mean, if it gives me a reading of zero Ohms, that's obvious, but what if a small (4.7uF), medium voltage (35V) cap comes up with a reading of, say, 3 Ohms? Is that too low, like I expect, or should it be co...


PSU for valves

Started by Peter in sci.electronics.basics2 months ago 12 replies

I thought I'd experiment with a few valve circuits (just for fun). So I'll need an H.T. power supply and I'm looking at...

I thought I'd experiment with a few valve circuits (just for fun). So I'll need an H.T. power supply and I'm looking at this: https://www.timstar.co.uk/el120300-high-tension-ht-power-supply.html It supplies up to 300V at 60mA. My question is, is 60mA sufficient? -- When, once, reference was made to a statesman almost universally recognized as one of the villains of this century, in order...


Why So Many Products With Poorly Designed Parts Still Do the Job

Started by Bret Cahill in sci.electronics.basics2 months ago 3 replies

At first you wonder how they got the difficult part correct and screwed up the easy part. The parts that fall apart aren't really necessary so...

At first you wonder how they got the difficult part correct and screwed up the easy part. The parts that fall apart aren't really necessary so you can still use the thing. Often it is better stripped of the unnecessary junk. So why are only the frivolous extras breaking? This is easy to explain. They put the bright people on the essential difficult part and the less competent people o...


Thermostat

Started by Olden in sci.electronics.basics2 months ago 7 replies

Best to ask here or ? My gas furnace is a Holly. It has an old mercury two wire thermostat. I want to change the thermostat so that I can...

Best to ask here or ? My gas furnace is a Holly. It has an old mercury two wire thermostat. I want to change the thermostat so that I can set the same two temperature ranges, day / night, for every day. I do not understand thermostats. The local store does not know how to advise me. Thermostat suggestions please and maybe a little tutorial.


Really Basic Power On Question

Started by Bret Cahill in sci.electronics.basics2 months ago 1 reply

This must be a really really common problem and the only reason it is diffi= cult to find on youtube is the wrong search terms: If a device...

This must be a really really common problem and the only reason it is diffi= cult to find on youtube is the wrong search terms: If a device has a power on button latch switch and you want it to turn on a= nd off like a light bulb, i. e., when the power supply is plugged in or a r= elay connects the power, or for solar, when the sun comes up, is it a commo= n solution to run a wire from th...


Use resistor instead of regulator?

Started by John Doe in sci.electronics.basics2 months ago 35 replies

I can put a resistor after a voltage that's too high for the circuit? Of course the resistor must handle the current. A decoupling capacitor...

I can put a resistor after a voltage that's too high for the circuit? Of course the resistor must handle the current. A decoupling capacitor after the resistor. Any problems with that? Thanks.


3 phase AC to DC

Started by malua mada! in sci.electronics.basics2 months ago 5 replies

I am running 3 phase AC into a set of transformers, Y config, and thence into bridge rectifiers . One leg of the output side of the transformers...

I am running 3 phase AC into a set of transformers, Y config, and thence into bridge rectifiers . One leg of the output side of the transformers goes to the diodes. the other leg to the Y connection. That Y connection gets warm. (why?) Should it be connected to DC ground?


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