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86164.0905 seconds (23 h 56 min 4.0905 s or 23.9344696 h). Another way to understand this difference is to notice that, relative to the stars, as viewed from Earth, the position of the Sun at the same time each day appears to move around Earth once per year. A year has about 365.24 solar days but 366.24 sidereal days. Therefore, there is one fewer solar day per year than there are sidereal days, similar to an observation of the coin rotation paradox.[5] This makes a sidereal day approximately 365.24/366.24? times the length of the 24-hour solar day. https://adsabs.harvard.edu/full/1984IAPPP..17...55D Pages 55 ~ 61 I received an email asking "What is sidereal time and where is it used?" And "How do you derive it from 60Hz?" Wiki has a fairly good article on sidereal time. Sidereal time is used by astronomers. There are special motorized drives that change the azimuth (degrees north-south) and elevation (height) to keep a star centered in a telescope Any sane person uses a app for their Android or iPhone. But there are special people like My Crazy Cousin who lives north of Santa Fe who is an advanced amateur astronomer. Anyway My Crazy Cousin wanted a dual display clock, one display would show Mountain Standard Time, the other Sidereal time, both synched to WWV. I happen to have some unused National Semiconductor LSI MM5314 single IC clock chips. I used green 7 segment LEDs for the MST and red 7 segment LEDs for the Sidereal. I used an inexpensive precision 10MHz canned TTL oscillator with internal heater. She upgraded to a ~$150 GPS disciplined oscillator with a 10MHz output. I used a PIC programmed with magic code to convert 10MHz to 60MHz. http://leapsecond.com/pic/ http://leapsecond.com/pic/picdiv-list.htm scroll down to pd60.asm:; PD60 -- PIC "4-pin" frequency divider (10 MHz to 60 Hz) You feed 10MHz into the PIC and get 60Hz out, the accuracy of the 60Hz depends on the accuracy of the input 10MHz. Then open https://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1984IAPPP..17...55D&defaultprint=YES&filetype=.pdf And you see one way way to modify 60Hz to feed "sidereal 60Hz" to a LSI clock chip to display sidereal time. I used the same logic but with CMOS chips. Now if the Leapsecond.com only had a 10MHz to "60Hz Sidereal"..... Now as I said at the beginning, any sane person would use an android device, perhaps an older tablet for a nice large display....but My Crazy Cousins "observatory" is in a marginal cellphone coverage so she maybe she isn't so crazy. [She also happens to be my favorite cousin. A really nice if somewhat dingbatty person.] My personal GTM/EST/Sidereal clock uses 3 MN5314, on for each time zone and uses the chip enable pin to turn on the desired time zone. Of course mine was built from 1976 through 1980 in stages. I came up with a logic circuit using 74LS chips that achieved the same function. I replaced my 74LS design with the new CMOS. Unless you are an astronomer, or total geek, you will never need sidereal time, but this is one 'easy' way to obtain it. Of course she could simply have spent ~$200 at https://brgprecision.com/products/stand_alone_clocks/sidereal.php Note 1: I've never actually used the Sidereal function, the only really clear nights in Kentucky suitable for astronomy are when there are no clouds and it's -10...and I'll be inside where it is warm and either asleep in our bed or listening to shortwave. Note 2: The CMOS 7555 are a Xitch to get working properly! Note 3: I saw a scheme in a British or German electronic hobbyist magazine that used logic to switch the 50/60Hz input from 60 to 50 every so many cycles to obtain sidereal time. It's been over 50 years I don't recall the circuit. Note 4: For a really hard way to get regular and sidereal time https://www.worldradiohistory.com/UK/Practical-Electronics/80s/Practical-Electronics-1981-10.pdf Note: 5: It should be possible to use the leapsecond.com 10MHz to sidereal 1 pps to drive one of those cheap analog clocks. They have a 32?kHz crystal, "IC" to produce 1 PPS, it'd require some experimentation but it should work. Since M

Amazon offers: 10K Temperature Sensor Probe https://www.amazon.com/DROK-Waterproof-Temperature-Thermistor-Transimitter/dp/B01MR37GOQ I found one even cheaper on TEMU. The WTESKE Manual says: Type of temperature probe R25 = 10K ohms +/-1% B25/85=3435K+/-1% It is a two-wire probe. Before ordering, I thought it might be prudent to check to see if the controller had been damaged when the original probe melted. When the probe is removed, the display blanks out - Open Circuit. So, it would appear that some resistance is required for the display to indicate the current temperature. Question: What value of resistor might be needed to fool the controller into thinking there was a working R25 = 10K ohms +/-1% sensor installed? -- G.T.

There is a PI controller with certain AC behavior. I need to use this PI controller in order to drive a coil (current controlled oscillator) of 1.5 ?H inductance. For DC behavior at 10 mV input I need 50 mA current on the coil at most. PI controller has proportional and integrator property. How can I convert this behavior into a driver circuit? /g/electronics101/photo/296358/3878514?p=Created%2C%2C%2C20%2C2%2C0%2C0 /g/electronics101/photo/296358/3878513?p=Created%2C%2C%2C20%2C2%2C0%2C0

I am working on a Sabre Flashlight/Tazer combination. The LED has shorted but that is not the reason for this post. The charging circuit is very simple. The line voltage goes through a 684nFd cap to one side of a diode bridge rectifier. The other side of the bridge is connected to the other side of the line. The output of the bridge goes directly to a 4 pack N size Nicad battery pack. During the testing of the cap, the bridge lead to the cap broke. I have found replacements for the LED and bridge. I checked the value of the cap by using my function generator and scope to make a divider with a resistor and calculated the cap value. It calculates to 730 nFd. A little more than 20% low. My question has to do with the limiting of the bridge output. Since there is no voltage or current limit, what provides these two limits? Also should this cap be replaced due to its low value. There are no markings on the bridge other than the input sine wave and the output +/-. I will replace this with a 1A 1000V bridge. I have selected a 1 Watt 3.4 volt 20 mm heat sink LED since this was the original connection configuration. I am considering adding a 5 volt zener and resistor on the bridge output just to limit the bridge output. Any thoughts? Regards, Dan Kahn

OK, cannot include a PHOTO of the connection diagram on the 3PH 3/4HP motor in question. However it is rather a simple matrix diagram of nine points of connection: o o o o o o o o o They are labeled as follows: LOW VOLT CONN LINE-1-7 4 LINE-2-8 5 LINE-3-9 6 HIGH VOLT CONN LINE-1 7-4 LINE-2 8-5 LINE-3 9-6 So, for the LOW VOLTAGE (208V) the CENTER connections are jumpered (/) to those ar LEFT and, for the HIGH VOLTAGE (480V) the CENTER connections. The label states "TO REVERSE DIRECTION INTERCHANGE ANY TWO LINE LEADS" DO YOU KNOW if this means Connect LINE 1 to connector 2 and LINE 2 to connection 1 ? Or connection LINE 1 to connector 8 and LINE 2 to connector 7 (LOW VOLTAGE CONN) and connector 7 to 5 and connector 8 to 4 (HIGH VOLTAGE CONN)? NOTE: I cannot see the motor itself, nor the connectors - just the label. I am wondering if the LINE connections from a THREE PHASE SOURCE are numbered One, Two, & Three respectively indicating the direction / sequence of the phases such that swapping LINE 1 with LINE 2 would actually reverse the motor's direction. -- G.T.

The following items have been added to the Files area of the [email protected] group. /Sabre Zapper.pdf By: Dan Kahn <dankahn88@...> Description: Sabre Light/Zapper

Radio shack used to sell a board that they called a "Stereo Headphone Amplifier", which basically supported a pair of LM386 chips and supporting components. Some years back I found one at a hamfest for some really low price and snagged it. Built the board, put it in a minibox with both RCA and quarter-inch connectors at inputs and outputs, and found a suitable wall wart to power it with (also originally from Radio Shack, as it turns out). There were a few different options for things like gain, rolloff, etc. that you could configure on the board with jumpers, I elected to route these to mini toggle switches. Sometimes when I power this thing up it'll break out into oscillation. Turning the volume control all the way down will usually put a stop to that, but I'd like to find out what's going on and put a stop to it. *ALL* of the connectors are grounded to the box. Is it likely that this has something to do with it? Something I was reading not too long ago had input connectors isolated from the physical enclosure, due to "ground loops" or something like that. Could this be the cause? -- 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

Hello , I tried to check the stability of the circuit by opening the feedback loop and placing the pertubation as shown below. How ever I made two plots Vf anole and Vf,Vin in AC responce and I get quite different result. What is the proper way to test feedback responce? Thanks. /g/electronics101/files/john233/classA_driver_new.asc /g/electronics101/photo/296358/3872575?p=Created%2C%2C%2C20%2C2%2C0%2C0 /g/electronics101/photo/296358/3872574?p=Created%2C%2C%2C20%2C2%2C0%2C0

I'm a sucker for test equipment, more so for good equipment at rock bottom prices. A friend dropped an inexpensive audio oscillator by for me to check out. https://www.akitika.com/1kHzOscillator.html#:~:text=Distortion%20is%20very%20low%2C%20typically,only%202nd%20harmonic%20is%20visible.) This oscillator has a claimed distortion of 2 parts per million (0.0002%). I only have access to test equipment that can measure down to 0.001% and this oscillator's distortion was lost in the noise floor of the test equipment. The frequency was slightly off, well within specs but 1002.31Hz. At $89 this represents an amazing value. Yes you can download their assembly manual and "roll your own" but I doubt you can achieve the performance of this unit. Part of their magic is their PCB layout and hand selecting the frequency determining devices. It isn't worth my time and energy to try and copy their PCB and locate accurate parts. I'm well know as a cheapskate and I ordered one.

I was given this little thing a while back, haven't done anything with it yet... There's this board, no particular identifying marks on just what it is. The oddest BNC I've ever seen on top, some switches down the left side that seem to be for selecting sensitivity and coupling, some DC input connectors on the top to power the thing, five buttons labeled OK, +, -, SEL, and RESET. A couple of pin headers and a USB micro connector on the bottom. A plug-in board labeled "2.4" TFT LCD. Two bits of paper came with it. One is labeled Oscilloscope DIY Kit User Manual but it seems to be assembly instructions. This bears the numbers 138803K and 13804K, no indication as to which unit I have here. The other paper has "How to Use" calling out the "Display and Controls". And some stuff about "probe calibration". On the back of that one are schematics that are barely readable. With a magnifying glass I see them showing power input as "9.39V". (!) Apparently some of this thing runs at 3.3V also. There's no case, though I'm told that one is available. Not told where, though. Have any of you guys run across anything like this? I'm a little dubious as to how useful this thing might turn out to be, haven't yet gotten around to digging out an appropriate wall wart to power it up... -- 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

If you are only interested in looking at audio on an oscilloscope, one decent method is to use a "high quality" USB audio interface. The Behringer UMC202HD is a decent unit that can be found at several music stores for around $100. Behringer enjoys a mixed reputation, apparently if you get a good unit they will work fine "forever." My three have been in nearly daily services for 4 years now. They are used as the analog to digital converter as a test instrument and to feed AF into a PC for audio analysis/decoding on a shortwave radio and one is used as an actual musical instrument input device. This circuit is used for the oscilloscope input conditioning. PC Oscilloscope Interface https://sound-au.com/project154.htm And these circuits are used for radio to PC, PC to radio PC To PA System Interface https://sound-au.com/project133.htm I used parts I had on hand so my circuits are slightly different. We use similar circuits to feed PC to/from our church's PA system and I carry a pair with my laptop just in case I find myself pressed into service as PA source or recorder. The PC to PA system interface will also function as a basic PC oscilloscope interface. For those who wish to study audio distortion, Mr. Elliot has some interesting, and downright weird, techniques. Intermodulation - Something 'New' To Ponder https://sound-au.com/articles/intermodulation.htm#s4 And Distortion Measurement System https://sound-au.com/project232.htm One can get by with a less then stellar USB AF device. Some well respected AF amplifiers show some surprising weaknesses when tested this way.

Hello, I have built a system shown below by the attached article.Its a frequency locked loop. basicky I am using a YIG as VCO to tune it exactly to the cavity resonator. The phase and amplitude of the resonance shown below. The mixer acts as a frequency discriminator by the behavior in photo 3. So if we input a tone at some frequency and look what IF (error voltage) we get at point B as shown in photo 4 and 5 . The main problem I have is the YIG VCO. The YIG has two coils which we tune. A large coil call "tune" and a small coil called FM. The large "tune" coil is being fed near the resonance area,while the smaller FM coil is the coil I use to tune the error of the mixer IF (frequency discriminator) which compares the signal coming from the cavity resonator and the signal coming from the YIG. The second coil is FM coil: 1.5uH inductance and 1Ohm resistance FM coil. sensitivity 400Khz/mA The main problem is that I am tuning the error using the FM coil while the tune coil (which is biased by constant voltage) is not in the feedback fixing mechanism I only have the FM coil to compensate for the gap between the YIG and cavity signals. I was told to use a PI controller(between the IF output and YIG input )to compensate fro the tune drifting. Is there some strategy on how what parameters the PI controller should have to compensate for the exteral frequency drifting caused by the tune coil? Thanks. /g/electronics101/files/john233/High_spectral_purity_microwave_oscillator_design_using_conventional_air-dielectric_cavity%20%284%29.pdf /g/electronics101/photo/296358/3871687?p=Created%2C%2C%2C20%2C2%2C0%2C0 /g/electronics101/photo/296358/3871686?p=Created%2C%2C%2C20%2C2%2C0%2C0 /g/electronics101/photo/296358/3871685?p=Created%2C%2C%2C20%2C2%2C0%2C0 /g/electronics101/photo/296358/3871684?p=Created%2C%2C%2C20%2C2%2C0%2C0 /g/electronics101/photo/296358/3871683?p=Created%2C%2C%2C20%2C2%2C0%2C0 /g/electronics101/photo/296358/3871682?p=Created%2C%2C%2C20%2C2%2C0%2C0

Been playing with various chinese-originated latching relay solutions from Amazon. Most are 'overly optimistic' about capabilities. Very 'overly optimistic'. Otherwise the rest have issues operating in environment with heavy canbus, Bluetooth, pwm alternator, 2M xceiver, and brushed engine / HVAC fans. Reaching way back in my mind, I seem to remember JK flip flops toggling output when strobed if J&K are tied high. Maybe it wasn't JK, but another type? Important points being that outputs are low upon turn on, and stroking with momentary (debounced) switch (high input). I am thinking that can tie outputs to darlington driver array, like ULN2803 or similar. Up to 1/2A current, 50vdc max, designed for inductive loads. Haven't found any information on temperature control yet. Not sure if I am reinventing the wheel. I do know that relays / contractors that utilize magnets for latch hold are probitive physically and way overkill. Incidentally, relay outputs will be controlling multiple isolated power supplies. Need around 16ch of mixed outputs. Suggestions or alternatives if I am on wrong path? Tomorrow I will be trying to find 32/64 bit versions of LTSpice (or similar) as my 486DX4 based PC (500MB drive and 8MB Ram!) 16/32bit machine died during Hurricane Beryl. ~SD

Hello,I have the following old mixer called TXF-18075 which I want to test for saturation and power levels in down converting mode. I dont have any datasheet only this brief table I found.Unlike amplifier A mixer needs two input powers the RF and LO. How can I see In my lab two things: 1.What is the needed LO power? 2. How can I see mixer saturation using lab equipment? Thanks. /g/electronics101/photo/296358/3870599?p=Created%2C%2C%2C20%2C2%2C0%2C0

Hello: I am Ken Gordon, am now 82 years old, and have been involved in electronics since I was 13 years old in 1956. So, recently I have been involved in "Elmer-ing" a good friend who is not particularly adept at electronics. I have been helping him get his ham station operable on digital modes. He bought a new Acer laptop to use for these modes. While trying to get Fldigi installed, we discovered that his Acer laptop's USB ports' two data lines are reversed from all others we have dealt with up to this time: i.e. Data - (minus) and Data + (plus) are "reversed" in his new machine. This, apparenty, doesn't matter when those lines are used for USB devices such as a mouse or a USB powered CD drive, but that DOES matter when those data lines are used to pass audio to/from the computer to the digital interface (in this case either a SignaLink or a DRA device). I thought it might be easiest for me to make him a short jumper cable out of a short USB extension cable by cutting it, and "cross-wiring" those two data lines. However, upon opening the cable, I find not 4 (or 5) wires, but a total of 11, 3 of which are obviously grounds. I have not yet been able to "ohm-out" the wires vs connections since I must make a needle-point adapter for my VOM, but in the meantime, here are the wire colors. First, separate black, white, green and red. These should be the standard + and - 5 V and Data + and Data - But there are two "bundles" of other wires, These "bundles" contain a slim bare wire and two other thinner wires, pink and purple in one "bundle" and blue and yellow in the other. Might anyone here have a clue as to what these are, or how they are wired? Ken Gordon W7EKB Virus-free.www.avast.com

This is only relevant for this group because we deal with science, or at least I assume the study and practice of electronics is scientific. A friend suggested this book and I just finished it....I'll avoid any rants about how the left needs to get a clue. Higher Superstition: The Academic Left and Its Quarrels with Science Read it and cringe..... To me a pound is a pound, a kilogram a kilogram, numerals go from 1 to as high as you want to count, social repression has nothing to do with any of the proceeding. Note, I don't especially like the metric system but I accept it is real and valid. It is worth noting the book was written in 1994, well before the current social conflict over woke, social justice, DEI, et al. To me a business exists to make money, Proctor and Gamble's Gillette's "We Believe" ad campaign credited with causing a $5 billion dollar loss. I'd be a little upset if I were a stockholder... [For those who require proof, do a net search or https://pguru12.medium.com/procter-gamble-three-year-after-gillettes-we-believe-ffa9c82d9772 "A major development was reported between late July and early August, when it was announced that Gillette had lost $5 billion in quarterly sales, resulting in P&G giving Gillette an $8 billion non-cash writedown in terms of valuation." Or look into Bud Lite....and what a debacle.] "Go woke, go broke." [I believe John Ringo, SF author, came up with that witicism.] A society that turns it's back on science or uses social criteria to decide scientific truths is in deep trouble. I'm reminded of the Indiana Pi Bill, look it up on wiki and laugh, then look at the current social situation. I bet it'd pass today. I actually heard an English professor in college complain that "Pi should be rational, it just isn't right....makes no sense." I kept my mouth shut because as an EE major I was alread on thin ice for studying something real. <you had to be there> Hum, reality isn't right or wrong, but it is real. [and yea Quantum Mechanics gives me a stomach ache, but it's real...for various versions of real.] If you can't remember 3.1415, maybe you shouldn't teach or vote. [If you only have a 4 banger calculator, a very close approximation to Pi can be found with 355/113. Give it a try...] [A friend used Pi to 25 places, backwards, as her master password to the Big Iron in college. Yea I know some odd people.] We have the most advanced civilization in the history of the planet, people in third world nations enjoy cell phones, computers and instant communication. One might expect this to lead to an appreciation of science. [When I see the ISIS or Starlink satellites I'm filled with wonder that we've come so far so fast. I remember John Glenn atop that rocket...poor BW TV in school.] I wonder how long before they start burning us at stake for being heretics in the current social structure because we believe 1 and 1 are 2, not the result of some inherent racial paradigm. [My wife read this, "Oh don't be silly, they won't burn you at the stake, they'll simply send you to a special camp to be reeducated.] I just heard a rant on the radio about the inherent racism in math which lead me to write this....I wanted to call in and as "so which numeral is an oppressed minority?" But decided against it as trying to convert a rock to life by lecturing it. Or get our cat to not twine between my legs as I try not to trip over her. Both tasks are futile.

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.

Hello,I have built a PI controller I have its time domain step responce and AC responce. PI controller is supposed to help with the DC part of the error signal of a PLL system. I cant undertnad how,Is there away i could see it? /g/electronics101/photo/296358/3866087?p=Created%2C%2C%2C20%2C2%2C0%2C0 /g/electronics101/photo/296358/3866088?p=Created%2C%2C%2C20%2C2%2C0%2C0 /g/electronics101/photo/296358/3865523?p=Created%2C%2C%2C20%2C2%2C0%2C0 /g/electronics101/photo/296358/3866089?p=Created%2C%2C%2C20%2C2%2C0%2C0 Thanks.

A company that offeres every RF connector in the universe, if they don't have it, it doesn't exist. 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. 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. Note: I have nothing to do with Brache other then as an amazed neutral observer. 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. Note: I have nothing to do with Pasternak other then as a satisfied customer.

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. https://sound-au.com/appnotes/an005-f1.gif 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!]