Re: typing Greek letters or math symbols
You can use synonyms in the program aText. For example, if I write oohm with a capital first O, the word is replaced with the Ω symbol. ? ? I normally type in a special font for dyslexics, Dyslexie. I can go to character map and snag Greek letters and other symbols, like those used in math, but it is a royal pain while typing. ? For serious writing, I place {} around the normal ASCII English letter and then I'll go back and replace them after I finish, in TV we called it "We'll fix it in post." ? I find trying to engage number lock and press alt while trying to remember what key to press for what Greek letter I want to be a bit too confusing, of course I could make a cheat sheet, that I'd have to keep track of.
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A company that offeres every RF connector in the universe
A company that offeres every RF connector in the universe, if they don't have it, it doesn't exist.
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I've been collecting RF adaptors since my first hamfest, 1966, and, we used an ungodly mess to adapt his odd equipment.
He found Brache Manufacutring LLC Newport Beach California.
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Their catalog has connectors I've never seen! And that's saying something!
Their prices are reasonable considering the oddity of some connectors and if the quality of the adaptor my friend received is any indication, they are a first class company.
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Note: I have nothing to do with Brache other then as an amazed neutral observer.
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Another company I have dealt with is Pasternak, they have a lot of microwave connectors and other components such as RF relays, but nothing near the number Brache has. Pasternak's products are also first class.
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Note: I have nothing to do with Pasternak other then as a satisfied customer.
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typing Greek letters or math symbols
I normally type in a special font for dyslexics, Dyslexie. I can go to character map and snag Greek letters and other symbols, like those used in math, but it is a royal pain while typing.
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For serious writing, I place {} around the normal ASCII English letter and then I'll go back and replace them after I finish, in TV we called it "We'll fix it in post."
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I find trying to engage number lock and press alt while trying to remember what key to press for what Greek letter I want to be a bit too confusing, of course I could make a cheat sheet, that I'd have to keep track of.
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Re: Peak crossing switch......
Hi Mikek, I am sorry for your headaches. The symbol shows up fine on Windows, even on the received email.? I typed “Alt +230” for the Greek micro symbol. I am curious what system you are using.? Also, your symbols are displaying OK on the email. Bertho ?
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From: [email protected] <[email protected]> On Behalf Of Mikek
Sent: 21 December, 2024 9:07
To: [email protected]
Subject: Re: [electronics101] Peak crossing switch......? On Fri, Dec 20, 2024 at 04:03 PM, wn4isx wrote: [Damn I wish this font had Greek characters!]
Do you mean this ▲ (hold alt while typing 30) or this δ (hold alt while typing 235)?? AKA, alt +30 and alt+235 Ω = alt+234, ? = alt+230,? π = alt+227?? β = 6Alt+225
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Re: Peak crossing switch......
On Fri, Dec 20, 2024 at 04:03 PM, wn4isx wrote:
[Damn I wish this font had Greek characters!]
Do you mean this ▲ (hold alt while typing 30) or this δ (hold alt while typing 235)?? AKA, alt +30 and alt+235
Ω = alt+234, ? = alt+230,? π = alt+227?? β = 6Alt+225
??????????? Mikek
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Re: Peak crossing switch......
If we arbitrary guess on a total series resistance of 100 Ohm and 0.5?F and 150V, you ought to see a peak current of 1.5A and an RC pulse duration of 50 ?seconds. ? To make the setup much easier and safer, I would use a DC power supply. Bertho ? ?
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From: [email protected] <[email protected]> On Behalf Of wn4isx via groups.io
Sent: 20 December, 2024 21:22
To: [email protected]
Subject: Re: [electronics101] Peak crossing switch......? The series resistance will be the AC Mains wiring and triac. The resistor goes from the triac to neutral to insure the triac behaves. There is also a 1M resistor across the 0.5uF capacitor and a push to fire switch. Do you believe a Siglent SDS 1202X-E can capture the transient. BTW. I've already added the resistor to the LED tube circuit.
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I just checked a non contact voltage detector on our ancient series Christmas tree lights.
[They were my wife's family, I'd toss them if it were left to me. I hate series lights!]
Anyway, the string was dead, as expected. The first pass didn't? catch anything. probably because the hot was on the 'cold' side. I reversed the AC plug and the 5th bulb was blown. Easy peasy.
Now if I can just get her to change to LEDs.......
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To check LED light strings make a hi-z JEFT front end for an AF amp, slide along the cord and the hum should drop when you reach the open bulb.
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I once had a commercial device called a or the "Ticker" that used this principal. I loaned it and the person moved before returning it.
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Never ever loan illreplaceable tools.
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Re: Peak crossing switch......
The series resistance will be the AC Mains wiring and triac.
The resistor goes from the triac to neutral to insure the triac behaves.
There is also a 1M resistor across the 0.5uF capacitor and a push to fire switch.
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Do you believe a Siglent SDS 1202X-E can capture the transient.
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BTW. I've already added the resistor to the LED tube circuit.
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On Fri, Dec 20, 2024 at 04:19 PM, wn4isx wrote:
Oooo mushroom cloud...so cool, my favorite man made cloud.
I call it the genie was released. Problem with all these electronics is that once the genie escapes, it does not work its magic.
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BTW, I designed up a zener diode checker using an LED driving circuit. Works well for those HV diodes. I am currently redesigning a HV CRT display power supply at work. The zener diode checker will work with zener diodes up to 130V breakdown. Furthermore, it is nice as it has different current ranges so one could also use it to reverse test a basic diode. I even used it to debug my LED Christmas light string. I will have to post it some day.
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Re: Peak crossing switch......
For product testing/approval I did a circuit years ago that allowed me in software to turn it on at any point. Basically, an opto to get line sync, a variable delay and a heavy-duty relay.? The software compensated for the relay delay. It also had a random mode and controlled duration glitches. I will upload the sync pulse generator. ? Capacitor current: If you connect a capacitor to a voltage source the capacitor will charge to that voltage.? There will always be some series resistance. The current vs time of course follows the RC charging curve. The starting current is only limited by the series resistance in the circuit.? Regardless of capacitor value. How long the pulse is depends on the capacitance. In the example with 150V and 100 Ohm you would get 1.5A, If 10 Ohm, 15A. I have a feeling that I am writing stuff that you obviously know.? Just forget about AC and rewind to electronics 101 ? ?
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From: [email protected] <[email protected]> On Behalf Of wn4isx via groups.io
Sent: 20 December, 2024 19:03
To: [email protected]
Subject: [electronics101] Peak crossing switch......? Does anyone have any idea how difficult it is to arrange a circuit to apply power to a DUT (Device Under Test) only at peak voltage? On both halfs of the 60Hz waveform? ? It is an imperial PITA on steroids! ? I went with a NE555 triggered at the zero crossing point and timed half way from that point for peak voltage. ? Simple zero crossing pulse generator to start the NE555 cycle.
? I used a 4N27, the output transistor drove another transistor, Darlington configuration. This drove a 600V 6Amp?Triac?by Teccor Part# Q6006F52. ? I used a 300 ohm 100 watt resistor (I have all sorts of odd stuff) as the load to insure the TRIAC would turn on and off. The turn on and off was OK but the timing was anything but OK. ? The output drifted around the peak but never was remotely stable. ? I was ready to give up when a friend said "Terry just use a 2 wire light dimmer module, they'll let you set for peak and hold it. ? My friend brought over several Hubble dimmer and, after some rewiring, I have a peak current turn on power supply. ? Note: Use a dimmer with dual RC network for increased stability. ? ? Now tomorrow or Sunday or Monday or someday really soon now I'll check the peak current through a 0.5uF capacitor. ? Now the real question, will a Siglent SDS 1202X-E capture the transients as the capacitor charges from the rapid delta-V? ? [Damn I wish this font had Greek characters!]
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The following items have been added to the Files area of the [email protected] group.
By: Bertho <boman33@...>
Description:
Line sync pulse Generator
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Oooo mushroom cloud...so cool, my favorite man made cloud.
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My first attempt at a quasi comp amp based on 2N3055 worked fine with Jefferson Airplain White Rabbit...right up until "Tell 'em a hookah-smoking caterpillar", made it halfway throiugh catepillar and became a genuine a firegod sacrifice with a nice, if rather small, mushroom shapped cloud.
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I was at school using their scope to check for ultraonics....
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My first decent self made, self etched PCB, amp, and power supply all went up nicely.
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It was also so silent.... until the heat sensor over me went off.
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This was way pre-smoke detector.
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It was so much fun explaining to the firemen "Well you see it was an amplifier..." their looks were priceless.
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And yea I really should have used a fuse in the V+ power rail.
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The post mortum suggested both 2N3055 shorted.
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Fuses are mandatory, not an option.
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Peak crossing switch......
Does anyone have any idea how difficult it is to arrange a circuit to apply power to a DUT (Device Under Test) only at peak voltage? On both halfs of the 60Hz waveform?
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It is an imperial PITA on steroids!
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I went with a NE555 triggered at the zero crossing point and timed half way from that point for peak voltage.
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Simple zero crossing pulse generator to start the NE555 cycle.
https://sound-au.com/appnotes/an005-f1.gif
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I used a 4N27, the output transistor drove another transistor, Darlington configuration. This drove a 600V 6Amp?Triac?by Teccor Part# Q6006F52.
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I used a 300 ohm 100 watt resistor (I have all sorts of odd stuff) as the load to insure the TRIAC would turn on and off. The turn on and off was OK but the timing was anything but OK.
?
The output drifted around the peak but never was remotely stable.
?
I was ready to give up when a friend said "Terry just use a 2 wire light dimmer module, they'll let you set for peak and hold it.
?
My friend brought over several Hubble dimmer and, after some rewiring, I have a peak current turn on power supply.
?
Note: Use a dimmer with dual RC network for increased stability.
?
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Now tomorrow or Sunday or Monday or someday really soon now I'll check the peak current through a 0.5uF capacitor.
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Now the real question, will a Siglent SDS 1202X-E capture the transients as the capacitor charges from the rapid delta-V?
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[Damn I wish this font had Greek characters!]
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Fifty+ years ago , I tried using my Simpson 260 series 3 on the 5000V range to measure a microwave oven. When the mushroom cloud dissipated there wasn't much left other than the bakelite case. At least I had sense enough not to be near the meter or wires when the circuit was energized.
Hugh Gilbert
My 260-8 has these DC ranges: 0-1-2.5-10-25-50-250-500-1000V
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I like the solution to the wrong termination resistance....in some ways I wish my HV probe was like yours, I own a Pomona Electronics Model 3157. This is a HV probe with build in meter. The probe designed for plug in operation presents a much lower load on the HV source, mine has a built in "sort of accurate" analog meter.
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Back when I played with 6502, 6914, 6914A and 7404 image converter tubes, I had to use a borrowed electrostatic voltmeter, talk about high impedance....
[Rare and pricy!]
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BTW Pomona makes extremely high quality test leads and oscilloscopes and even nicer "Pomona Blue Enamel 2397 Electronic Project Boxes"
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But be prepared to pay premium prices.....
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For very interesting reading, see the works of Marie Curie. She was measuring nA currents 130 years ago.? It is incredible to see the detailed work done with the quadrant electrometer and piezo electricity. The working conditions were also poor. Bertho ?
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From: [email protected] <[email protected]> On Behalf Of wn4isx via groups.io
Sent: 20 December, 2024 13:19
To: [email protected]
Subject: Re: [electronics101] High Voltage Probes? My 260-8 has these DC ranges: 0-1-2.5-10-25-50-250-500-1000V ? I like the solution to the wrong termination resistance....in some ways I wish my HV probe was like yours, I own a Pomona Electronics Model 3157. This is a HV probe with build in meter. The probe designed for plug in operation presents a much lower load on the HV source, mine has a built in "sort of accurate" analog meter. ? Back when I played with 6502, 6914, 6914A and 7404 image converter tubes, I had to use a borrowed electrostatic voltmeter, talk about high impedance....
[Rare and pricy!] ? BTW Pomona makes extremely high quality test leads and oscilloscopes and even nicer "Pomona Blue Enamel 2397 Electronic Project Boxes" ? But be prepared to pay premium prices.....
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Roy,
The capacitor had an internal short. It measured 240nF with a Q of zero. It is supposed to be 1?F +/- 3%.
This was a very well-done service manual, 34 pages of pictures, schematics, disassembly procedure, and troubleshooting.
Well-done LG except that diode test.
The scope probe is Tektronix P6015 rated at 12kV.
Bertho
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-----Original Message----- From: [email protected] < [email protected]> On Behalf Of Roy J. Tellason, Sr. via groups.io Sent: 20 December, 2024 11:24 To: [email protected]Subject: Re: [electronics101] High Voltage Probes On Wednesday 18 December 2024 08:30:23 pm Bertho wrote: There have been several comments on high voltage measurements and
probes buried in various messages.
While fixing my microwave, I needed to measure the high voltage output
from the transformer. I have never seen the need to measure that. And I've worked on a few of those. As many have mentioned, a regular DVM cannot be used at that high voltage. Nope. But surprisingly a Simpson 260, at least as old as the one I have, will measure up to 5000V. I've never used those particular input jacks. I have a 1000 to 1 high voltage oscilloscope probe, but it is designed
for a 1MΩ load, not the 10MΩ of the DVM. I have a "HV Probe" bought back when I wanted to measure the "2nd Anode" voltage in CRT type TV sets, back when I was working on those. It'll measure up to 40KV. A rather impressive-looking beast. :-) Adding a 1.11MΩ resistor across the input to the DVM compensated for
the input resistance. Right. I double checked measuring the 120AC. The transformer output was 2,380VAC .
As usual do not do it if you really do not know what to do.
It was a bad high voltage capacitor. Bad how? Open circuited? Changed value? Surprisingly, the very detailed
service manual had a surprising error: It described testing the high
voltage diode in forward and reverse with a regular DMM using the
diode test mode. I think I've encountered *one* microwave that came with a schematic. None at all with anything that could be described as a service manual. It will read open both ways since the forward diode drop is typically
8V because of the stacked diodes. I'd wondered what it would take to forward bias one of those... -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, a critter that can be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin
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My 260-8 has these DC ranges: 0-1-2.5-10-25-50-250-500-1000V
?
I like the solution to the wrong termination resistance....in some ways I wish my HV probe was like yours, I own a Pomona Electronics Model 3157. This is a HV probe with build in meter. The probe designed for plug in operation presents a much lower load on the HV source, mine has a built in "sort of accurate" analog meter.
?
Back when I played with 6502, 6914, 6914A and 7404 image converter tubes, I had to use a borrowed electrostatic voltmeter, talk about high impedance....
[Rare and pricy!]
?
BTW Pomona makes extremely high quality test leads and oscilloscopes and even nicer "Pomona Blue Enamel 2397 Electronic Project Boxes"
?
But be prepared to pay premium prices.....
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On Wednesday 18 December 2024 08:30:23 pm Bertho wrote: There have been several comments on high voltage measurements and probes
buried in various messages.
While fixing my microwave, I needed to measure the high voltage output from
the transformer. I have never seen the need to measure that. And I've worked on a few of those. As many have mentioned, a regular DVM cannot be used at that high voltage. Nope. But surprisingly a Simpson 260, at least as old as the one I have, will measure up to 5000V. I've never used those particular input jacks. I have a 1000 to 1 high voltage oscilloscope probe, but it is designed for a
1MΩ load, not the 10MΩ of the DVM. I have a "HV Probe" bought back when I wanted to measure the "2nd Anode" voltage in CRT type TV sets, back when I was working on those. It'll measure up to 40KV. A rather impressive-looking beast. :-) Adding a 1.11MΩ resistor across the input to the DVM compensated for the
input resistance. Right. I double checked measuring the 120AC. The transformer output was 2,380VAC .
As usual do not do it if you really do not know what to do.
It was a bad high voltage capacitor. Bad how? Open circuited? Changed value? Surprisingly, the very detailed
service manual had a surprising error: It described testing the high
voltage diode in forward and reverse with a regular DMM using the diode test
mode. I think I've encountered *one* microwave that came with a schematic. None at all with anything that could be described as a service manual. It will read open both ways since the forward diode drop is typically 8V
because of the stacked diodes. I'd wondered what it would take to forward bias one of those... -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin
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Re: PI controller time domain responce in PLL from AC responce
On Fri, Dec 20, 2024 at 06:18 AM, john23 wrote:
My system is a frequency locked loop, ...
I could swear you said it was a phase locked loop.
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I get the feeling you do not seem to know what you are doing.? Am I mistaken?
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Andy
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Bertho
Derek Koonce