One project always leads to another

Thread Starter

Wolframore

Joined Jan 21, 2019
2,609
so having started my venture into designing switching power supply I got some great things to consider from the forum. Thanks @TeeKay6!

So I decided to draw up 6 designs to put on pcb and test. I think I need to get an RF spectrum analyzer. We have an unusually hot summer in Chicago. So I get to work and after 3 designs the circuit breaker trips. I lost two designs. I liked the third one.

Reset and it trips 2 more times. More work lost

Yes we have the AC going and it was my wife running the washer and dryer. I ran the dryer on separate 240 line when I moved in but the washing machine for some reason runs on the same circuit as my work area. So two trips to Home Depot and few hours later. Now the fricken washing machine which draws 10A is on its own 15A breaker. Wife said great job but something she just said shows she has no clue what I did. Just that I did something for the house.

I plan to trip the breakers and go around the house to figure out the idiotic things the people before us did. I found one line that has the same color wires for hot and neutral .

Thank gawd the breakers are inexpensive. I might be pulling more line soon. Then I remember I need to run some more outlets on their own breakers for the garage and all I want to do is get back to working on the pcb designs.
 
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dl324

Joined Mar 30, 2015
16,839
We have an unusually hot summer in Chicago. So I get to work and after 3 designs the circuit breaker trips. I lost two designs. I liked the third one.
We get a lot of power glitches when branches touch power lines. I have our two desktop computers on a 1000VA UPS, so brief brownouts and such don't affect the computers.
 

MrAl

Joined Jun 17, 2014
11,389
Hi,

We ended up doing that breaker find thing in an old house once too. Kitchen line problems.

One thing you can do is plug a vacume cleaner into an outlet and shut off breakers until the vacume turns off. It is loud enough to hear in the basement.
 

TeeKay6

Joined Apr 20, 2019
573
so having started my venture into designing switching power supply I got some great things to consider from the forum. Thanks @TeeKay6!

So I decided to draw up 6 designs to put on pcb and test. I think I need to get an RF spectrum analyzer. We have an unusually hot summer in Chicago. So I get to work and after 3 designs the circuit breaker trips. I lost two designs. I liked the third one.

Reset and it trips 2 more times. More work lost

Yes we have the AC going and it was my wife running the washer and dryer. I ran the dryer on separate 240 line when I moved in but the washing machine for some reason runs on the same circuit as my work area. So two trips to Home Depot and few hours later. Now the fricken washing machine which draws 10A is on its own 15A breaker. Wife said great job but something she just said shows she has no clue what I did. Just that I did something for the house.

I plan to trip the breakers and go around the house to figure out the idiotic things the people before us did. I found one line that has some colors for hot and neutral .

Thank gawd the breakers are inexpensive. I might be pulling more line soon. Then I remember I need to run some more outlets on their own breakers for the garage and all I want to do is get back to working on the pcb designs.
@Wolframore
I suggest that a good scope would be more useful than a spectrum analyzer when troubleshooting PS's. A set of equipment to monitor RFI/EMI/etc for regulatory approval is quite expensive; I always used (now retired) a UL/FCC approved lab for such testing (for products destined for sale).

Re house/power: I wired my own house completely; no thrown breakers. :) Separate breakers for all high power items (hot water heater, water well pump, clothes dryer, A/C, garage subpanel, etc) and unique items (e.g. refrigerator) that I might want "on" when all else is set off. I also clearly marked in the breaker box what was connected to each breaker. I turn off master breaker when lightning gets too close. (Learn from experience.) :)

Project & life rules: Every project is more complex than it first appears.

Weather: Central Texas, hotter & wetter than usual but no records broken.
 

Thread Starter

Wolframore

Joined Jan 21, 2019
2,609
I have a decent 200Mhz scope. I guess I’m a little spoiled from the awesome test equipment we had in the military. Spectrum analyzer is great you can do Fourier analysis and see where the affected frequencies are and narrow down the issues.

I hate working on the house. It’s a 2 story brick built in 1920 and I’m sure I can spend every weekend doing something but that’s just no fun.

Haven’t tripped any breakers since I broke it out to a dedicated circuit. There’s plenty of room for more when I need it.
 

Thread Starter

Wolframore

Joined Jan 21, 2019
2,609
Oh wow you’re right it does have FFT.. that’s useful. I guess I should read the manual. Lol. I miss the old gear we had. But I like my new scope I’ve had for a month and only needed it twice so far. It’s 200 Mhz but was not expensive. I like how light they are now but I guess it’s like my iPad. Just a big screen with some some analog circuitry as then ADC into processor.

But it’s only 8 bit vertical resolution. I believe the ones we had were completely analog. I’m guessing 24 bit ADC ones are really expensive for now. 8 bit is pretty lame. With all the 24bit ADC for audio you would think they have inexpensive front ends for these things. Come on at least 16 bits. Although as the sample rates get really high for the higher frequencies it will need a lot of memory which can prob use a high speed sad drive there. Give me 16 bits and 5 GHz. Or better yet analog...

As for FCC compliance you can’t certify your own gear but it’s good to know where you stand before sending out for testing.
 
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BobTPH

Joined Jun 5, 2013
8,804
It’s not the memory, it’s the speed that limits it to 8 bits. To get 200 MHz bandwith, you need 400,000,000 samples per second, or one sample every 2.5 nsec. That is not easy to do for 8 bits, let alone 24.

Bob
 

Thread Starter

Wolframore

Joined Jan 21, 2019
2,609
Yeah I get it... even 24Bit @ 192K (to capture audio) sampling gets taxing when I have to have 24 tracks of this plus all the processing summing.

I wonder how RIGOL does 7.5 GHz spectrum analyser with their DSA875... I couldn't find information about their sampling and ADC.
 
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