One rapid LED light pulse per press of push button switch circuit using 2N3904 NPN BJT
Just adjust capacitor to desired time interval, like 10uF or 22uF...
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One rapid LED light pulse per press of push button switch circuit using 2N3904 NPN BJT
Just adjust capacitor to desired time interval, like 10uF or 22uF...Last edited by harp; 07-05-2024, 10:53 AM. -
Latching relays need only a brief blip to their coil. Panasonic, Omron G6AK need 10msec pulse. Note that if you bang or bump the relay, it can unlatch so your firmware must bump it and never assume the relay is where you left it.
Had a voltmeter product people would drop and unlatch the range relays so it would then read stupid and get back for repair to our shop.
OP is basically looking for a power-on reset circuit and there are 1,000 ways to skin that cat.Comment
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correct, it should be in series not in parallel, alas, at 3.3V rail and the charge time, it shouldn't be too long until it's charged and shut off.
TBH dangit, i'm too used to cmos and ttl devices where input current limiting is implicit/built-in...aaaahhh...
Dammit I need to fix my Tek scope, one of the latching relays in it is stuck... *sigh* Not sure why Tek decided to use latching relays in their attenuators...Last edited by eccerr0r; 07-05-2024, 07:39 PM.Comment
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the scope probably uses latching relays to avoid any inductive coupling from a coil and the signal
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Latching relays are used where you want to save power, not have a coil energized all the time, like in battery-powered gear.
Also in precision voltage measuring gear, you don't want a relay heating up and adding a thermal EMF potential due to the dissimilar metals and thermocouple junctions inside a relay. So you'll see them in high end bench multimeters too.
If a relay (or reed switch) is sticking, I find it's because they get magnetized in one (pole) direction with age, the only one polarity they work in.
I will use an old cassette-tape head demagnetizer, or energize the coil backwards (out of circuit) to fix them. Not sure why but it works. I think some relays though have a bias magnet to make them more sensitive so then AC field would wreck that. Not sure.
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Yeah it's a line powered scope. The coupling problem seems sound but if it's driven by a DC signal, it should also be stable...
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Burco BCPLSAFWM5L 5 Litre Wall Mounted Automatic Water Boiler With Filtration UK 240v
Does anybody have any experience with these Burco units at all there is no record of them on the forum lol and a proper service manual would be nice. I invite you all to pesuade me not to botch repair it with a 5v relay, read on.
This unit was rescued from a skip 3 years ago, the only fault it had then was no backight display (plus it wanted a new probe set and top seal) but the screen was never an issue you can still see the screen as is and I just use it to get 5 Litres of very hot... -
I have a very small float switch, I'm using in a very small tank. It only fits in one way. Link https://www.amazon.com/uxcell-Switch.../dp/B07DZ1J2GB
I want the switch to be open when the water is high, and closed when the water is low. Unfortunately it works the opposite. And since this switch is designed to be underwater, it's all sealed up, there is no taking it apart or hacking it up.
It will be driving a water pump, basic idea, when the water is low, switch closes, which turns on water pump, when enough water is in the tank, float switch floats,... -
Hello everyone,
I'm turning to the Badcaps community to help me troubleshoot the radio Rx card from my (old) garage door opener. While I could just ditch that card and replace the whole system, I first would like to understand "why" it suddenly stopped working, because that's just how I am wired...!
Some basics: the receiver works on a 30.875 Mhz frequency. Yes, I'm aware this is not in use anymore in a looot of places. It does not use any rolling code, it's just a regular dip-switch code that you have to set up on both the receiver and transmitter. The receiver... -
This specification for the Acer Switch Switch V 10 SW5-017P Hybrid (2-in-1) can be useful for upgrading or repairing a laptop that is not working. As a community we are working through our specifications to add valuable data like the Switch V 10 SW5-017P boardview and Switch V 10 SW5-017P schematic. Our users have donated over 1 million documents which are being added to the site. This page will be updated soon with additional information. Alternatively you can request additional help from our users directly on the relevant badcaps forum. Please note that we offer no warranties that any specification,...09-06-2024, 05:30 AM
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Great to be here! I'm a newbie here trying to find a "micro", momentary push switch to repair a Sony "clamshell" video walkman. This micro switch has long since discontinued by Sony, however I hope there are third-party switches of the same size and functionality that I might be able to source to play the same role. The purpose of this switch is to tell the video walkman that the user has activated the mechanical tape eject button, turning that physical action into an electronic signal that tells the tape transport mechanism to open so one can load or eject a video tape. I...
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