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Hello, I am trying to understand the dinamics of the circuit taken from the youtube video. if we apply 2V DC the node 2 on the photo will be 1.4 (Vbe=0.6) The node 1 will expirience some voltage wich will be translated to the other PNP base. Could you describe how the regulating dinamics works here? Thanks. https://www.youtube.com/watch?v=nOOOAjoqCt8&list=PL4C141B35706AD19A&index=3 /g/electronics101/photo/296358/3896088?p=Created%2C%2C%2C20%2C2%2C0%2C0

A friend and fellow idiot sent me this link https://www.tesladownunder.com/WorldsBrightestBike.htm#BikeLights I am impressed and bow down to this guy. [and I'm glad I live nowhere close to him.] I gave up bicycles when I turned 16 for motorcycles with the logic "Now I can outrun cars...." They still don't see you, even at night with your headlight on drivers will cut you off with frightening regularity. I gave up on motorcycles after seeing two young riders get splatted by a 'queen mary' [any large car] while driving down the road. The bikers were in their lane driving sanely, the cars just ran them down. Anyway, the light from a Honda CA-77, CB-350, CB-360 wasn't anything to write home about and it was easy to outdrive your headlight, outdrive refers to driving faster than you can see ahead. [perhaps one shouldn't drive 80MPH on narrow back roads.....] Now this headlight would let you see far enough ahead to be useful....but blind the poor sod coming at you so he'd probably splat you. While I've kept my motorcycle endorsement, that's more because I'm stubborn then practical. There is no way I'd ride a motorcycle unless my life depended on it. I suspect my artificial knees would be most displeased. Consider the project as proof humans can do amazingly stupid things....I'm proud to be a member of such an inventive species. Worry about our long term survival chances, but what the heck, we can have fun in the mean time.

Previously wn4isx posted a link to: https://www.pa3fwm.nl/projects/miniwhip/ The reference refers to an improved version but there is no link to it. Does anyone know where I can find the improved version schematic? Any other suggestions? I remember seeing an article about installing an active antenna and avoiding extra local noise, but I do not remember where I saw it. Using SMT components is not a problem. Thanks Bertho

If you have projects that require data acquisition Ebay has several options but the gold standard would be Dataq. They offer a variety of data acquisition units, some are analog only, some feature analog and digital inputs. Their software is amazingly flexible and can allow you to view the data you've recorded in a variety of ways. Their most basic unit is about $50 but the drivers are for Windoze 10/11. It is possible to force an install under Windoze 7 64 bit professional but you risk breaking the install. I use Macrium Reflect disk imaging software so breaking an install takes about 6 minutes to boot the Reflect CD, snag the operational image and restore. There are many free disk imaging software packages out there, while I use Macrium Reflect, I won't pretend it is the best, but it was free and easy to learn to use. Being able to restore to a known good image makes it safe to try questionable software or configuration changes. I've broken ever version of Windows since Windows 3.11 For Work Groups. I went with the Dataq DI-1100 "Data Acquisition USB DAQ and Data Logger System, 12-bit, 20,000~40,000 Samples per second per channel. I actually have 4 DI-1100 in service. None has crashed. As of March 7, 2025 the DI-1100 costs $79 and comes with Dataq software. While the spec sheet says operation under Windows 7 will probably work, performance and unexpected errors are possible. I installed the drivers and software on a variety of HP PCs running Windows 7 64 bit professional. Your experience might be very different. I have an expensive data logger and analysis program that will only run under Windose, Wine and other Windose emulators for Linux don't work, yet. The software will load under Wine but doesn't properly work. So I'm stuck with Windows 7 64 bit professional for the foreseeable future. Dataq offers software for Linux but I have zero familiarly with Linux. The DI-1100 has 4 analog inputs with a +/10V range with a resolution of ±4.8 mV. [You can take a cheap sound card and bypass the input capacitor and use a resistive network to convert a cheap sound card to make a data acquisition unit. I've done this and it does work, might work pretty well, but is far less then optimal.]

Hello , I have designed a differentiator as shown below.The pulse in the simulation photos links below is 1ns which is 350MHz BW ,much higher then the BW of the AD8034 opamp.As you can see its working.How its possible? Why its differentiating the pulse although the opamp doesnt have such BW? Given the pulse what slew rate and what BW does the OPAMP need to have? https://eu.mouser.com/datasheet/2/609/AD8033_8034-1502231.pdf https://ibb.co/0VMSYCkQ https://ibb.co/tMkTLQt6 https://ibb.co/WpDF9Qch

No, I traded it to a WWII reenactor. My father bought the jeep new surplus in 1949. The state decided the original bill of sale was OK for licensing. The jeep ran fine in 1975 when Dad realized he wasn't going to drive it again. It had just over 400 miles on it. I suspect all the rubber would need to be changed. It was stored inside so the paint was like new. Fortunately there is a fairly large group of WWII jeep enthusiasts so parts won't be hard to locate. I 'learned' to drive in that jeep. Across cornfields that had been harvested. I'd just turned 9 and could barely reach the pedals and hang on to the steering wheel. And forget synchromesh transmissions, double clutching was an experience. Fortunately they were made for rough service. One thing about WWII jeeps is they have a high center of gravity and you can roll them in a heartbeat. I nearly managed it at 20MPH in fairly soft dirt when I turned too sharply.

The following items have been added to the Files area of the [email protected] group. /Temp/AD8034_differentiator.zip By: Andy <ai.egrps@...> Description: Examine the response of differentiator circuit that uses AD8034

OK I am weird, as a 3 year old (1954) I'd swipe my father's WWII MX-991/U flashlight. This is the standard right angle headed unit. I'd hide in closets, under the sink, under beds, in the small room the water heater sat in (under the stairs) and enjoy the light in the dark. Dad was frustrated, "D" cells weren't horribly expensive, but he grew tired of having to keep a supply. Mom took the view point "At least he's not using candles." A friend of Dad's worked for GE and gifted our family with early NiCad cells and a charger. Dad bought me my very own MX-991/U and I'd sit in the closet and listen to my "Boys Rocket Crystal Radio." My maternal grandfather gave me a very old Prango 2 "D" cell flashlight with a patent date of Sept 28, 1915. This unit uses a small silver plated "parabolic" reflector with a large glass lens. Thus began my collection of flashlights.....a collection continues to grow, I've never met a flashlight I didn't like. All of this is of historic interest and perhaps offers a view into my somewhat odd psyche, but what on earth does it have to do with Electronics 101. I could go into the vibrator powered electroluminescent light my dad built for me, or how my uncle replaced the vibrator with a pair of germanium power transistors, or how I made my first LED flashlight, it used red and green LEDs and either or both could be enabled, but I won't. [And for you with dirty minds.... https://en.wikipedia.org/wiki/Vibrator_(electronic)] Your portable electronic gear operates from batteries, unless you have a hand held generator or can operate off PV cells in direct sunlight. A friend gave me an interesting book. This book is almost mandatory for those of us who operate equipment from batteries Batteries in a Portable World: A Handbook on Rechargeable Batteries for Non-Engineers, Fourth Edition It is available at Amazon (and at the ARRL), it is a bit expensive at about $30. I still distrust secondary (rechargeable) lithium batteries, but they are a factor of modern life and, unless I wish to give up my cellphone, laptop PC, portable equipment, I have no choice but to learn to live with the !@#% things. The book starts out with the basics of batteries and might appear too basic for a serious hobbyist, but it gets down to brass tacks with reasonably detailed information on many different types of batteries, their strengths and weaknesses. And all batteries have both.

I have a Lorex wireless security system that uses it's own receiver for the outdoor wireless cameras. I just recently had another camera appear to fail but I can "pair" it with the receiver if I am within about 5 feet of it. Then as I move the camera away it loses connection. I replaced it with a new spare camera and problem solved. My question is can the camera possibly be repaired by me and what is the possibility it is just a bad capacitor or some other common component that would cause the limited range? I haven't opened it up yet but I just wanted to know if it is beyond repair or possibly fixable? Thanks

On Tue, Mar 4, 2025 at 08:37 AM, wn4isx wrote: Normal digital cameras are moderately sensitive to IR, ... I wonder if that's true of all of them. It probably is. Photons are photons. I know my first digital almost-SLR from 20+ years ago could, and I considered having the modification done to it. I love IR photography, but never experimented with it. I'm afraid it might become a "fad" that loses its appeal after a few hundred IR photos. The camera has a xenon flash that produces near zero IR. I have to illuminate an object with an array of IR LEDs. Can't you just use the built-in flash? Or did the camera's modification add an IR-only filter to the lens, making it insensitive to visible light? Andy

Dave <theschemer@...> added the photo album Lorex Wifi Camera : An image of the circuit board of my Lorex Wifi security camera that has lost it's effective range. The following photos have been uploaded to the Lorex Wifi Camera photo album of the [email protected] group. Wifi Camera.jpg By: Dave <theschemer@...>

Hello , I have a single ended PID and a vccs driver (differential ) What is the best way to connect the two, so the PID output will be driver input? Thanks. /g/electronics101/photo/296358/3889903?p=Created%2C%2C%2C20%2C2%2C0%2C0 /g/electronics101/photo/296358/3889904?p=Created%2C%2C%2C20%2C2%2C0%2C0

First, I have no financial stake in Electronic Goldmine, I'm just a satisfied customer. I needed some transformers for a special project and Electronic Goldmine started offering these. Microtran Pico Transformer PM34-M Miniature 600 Ohm C.T. to 600 Ohm C.T. 50mW Rating "Microtran Pico transformer type PM34-M is a miniature fully encapsulated 50mW rated 600 Ohm C.T. to 600 Ohm C.T. transformer. Frequency response is ±2db 300Hz to 100KHz. Has 6 full length leads. Size only 0.3" x 0.4" x 0.425" tall. New" at https://theelectronicgoldmine.com/products/g28678 Full specs can be found here https://www.technicalaudio.com/pdf/MicroTran/Microtran_miniature_transformers_catalog_1974.pdf Electronic Goldmine offers surplus, new old stock, components and probably doesn't have oodles of these. 60Hz appears be just over -3dB. YMWV depending on your system. Short pulses of 1 cycle or 1kHz show minimum ringing. These could be ideal for coupling a computer to a ham/shortwave radio, PA, or other interface needs.

does anyone know if these ( cCTI OCXO type OSC5A2B02_can work at different frequencys if the internal crystal is swapped for a different freq item?.

Hi , I have reports of distorted tx audio on my ft-767DX,is it possible to feed audio from my laptop headphone jack into the rig mic input, then tx the laptop audio into a dummy load via the radio then monitor the transmitted audio via a diode detector using a crystal earpiece while i make adjustments?.

This might be of interest to radio enthusiasts in this group. Cable TV systems have always had problems with RF leaking from and into their "closed systems." This is a bit one sided industry view that is nonetheless interesting. Read all 3 parts and then the Distributed Access Architecture. https://blog.viavisolutions.com/2019/08/28/how-air-force-one-forever-changed-cable/ At one point the local cable system used a pilot tone smack dab in the middle of the 2M ham band to set the automatic gain of their 'gazillion' line amplifiers. Their system leaked like a sieve and a group of local hams sat up an impromptu network on that frequency, which shut the entire cable TV system down. The cable system was violating the law with excessive leakage. The same technical flaws that result in leakage that allow radiation of cable TV signals also allows external RF to get in. The cable system issued vague veiled legal threats, which resulted in the FCC paying them a visit with an order "Clean up your act, now." The spent a not so small fortune upgrading their system. it took them less than a month. The engineers I worked with (and me) were offered nearly obscene amounts of money to pitch in. They needed more warm bodies with technical skill than exist in Was it a mean nasty act on the part of hams? The answer depends on which side of the fence you are on. Similarly, in the early 1980s the Grateful Dead played a concert in Lexington, their roadies made the mistake of using 70cm ham radio transceivers, which really upset the local ham radio community. Which lead to another impromptu net on the roadie frequency. They tried to change frequencies but the hams followed. The roadies finally gave up and did the setup the old fashioned way. The take away here is hams are tenacious bulldogs with rabies and an attitude when it comes to guarding/protecting their frequencies.

what buffer amp do i need to connect my sdr to my yaesu ft-707 to use it as a panadaptor,i am looking for a cct diagram so i can homebrew something,thanks.

Lost the battle of yard lights. Now we have a plethora of dollar store rejects hiding amongst the weeds. Neighbor was very appreciative of the copper 120vac lights. Beautiful fixtures after stripping, polishing and spraying a lacquer. Looks fantastic, so isn't my handiwork. Next project needs to be / remain battery powered, naturally selected Headway 38120 LFP cells. 3.2v 8ah (yes, *8aH*) with max rated discharge of 15C (120A). Since I have about 50 of the darn things, gonna use a few of them. Except can't find a single cell lfp bms / battery disconnect. 2S hard to find as well, unless direct from China Mainland. Load anticipated around 10w (max, pwm), basically a string of low voltage lighting. Solar panel is 6v-ish, feeds a epoxy-encased charge circuit that in turn charges an INR lithium 3.7v cell 3000mwh capacity, or about 900mAh. I can knock down pv voltage (currently) by shading cells, eventually rewire each half in parallel. PV cell output is (educated guesstimate) 6-ish vdc @ 2w. I do have a dozen or so of the PV panels. Still leaves me with discharge issue. If cells go under 2.5v, damage occurs. LED string becomes dark around 1.9v and current falls to a few mA. If I put a usual and typical silicon diode in series with cell output to led string, I expect a .7-ish V across diode. Add that to 1.9v string conductance threshold, and have a 2.6V drop, which should halt any appreciable current flow at under 2.5v.. Does this course of reasoning have merit, or shall I remain in the Dark Side? ~SD

On the subject of antennas: Lo-VFH pager antennas surprisingly are using the person’s body as the antenna. The body “antenna’ couples into the pager’s internal antenna when it is when worn on the belt. Worse performance if used in the shirt pocket. Motorola’s Pageboy 2 series use the U-shaped metal case as the antenna. I have spent too many weeks optimizing antennas and front-end designs for the Motorola pagers. From low band-VFH-UHF and finally the first 900MHz pager. I like the info on the active antennas, and I am itching to build one. I got an SDR that I played with 5-6 years ago, but I have to relearn how to use it, or maybe get an updated unit. Bertho

Hello, I have a mixer shown in the link below.The way I calculate the noise coming out of the mixer is as following: -174+NF-conversion loss=-174+0.5-6=-179.5dB/Hz so far I am correct? also the Mixer Noise Figure typically measures within +0.5 dB of conversion loss for IF frequencies greater than 5 MHz. However I was told that we add another 3dB because we convert noise from RF twice. If its true, Is there some visualisation I could use to see why we add another 3dB? Thanks. https://markimicrowave.com/products/microstrip/mixers/m1-0818ne-1/datasheet/