555 pin3 output

Started by RobH in sci.electronics.basics2 months ago 4 replies

I've been trying out a couple of Automatic Fence Lighting circuits with a 444, 741 and ldr. I posted earlier about the circuits above , and...

I've been trying out a couple of Automatic Fence Lighting circuits with a 444, 741 and ldr. I posted earlier about the circuits above , and the problem I had was that I could not get a buzzer to work from pin3 of the 555. I came across this https://www.electronicshub.org/how-555-timer-ic-testing-circuit-works/ and found that out of x3 555's I had which I thought were faulty, only 1 ...


Schmitt Triggers

Started by RobH in sci.electronics.basics2 months ago 32 replies

I have been looking at schmitt trigger circuits and didn't realise how many variations there are. Anyway I found this...

I have been looking at schmitt trigger circuits and didn't realise how many variations there are. Anyway I found this one: https://reviseomatic.org/help/2-radio/Schmitt%20Trigger%20Light%20Sensor.php The author here says that by adding a 22k resistor to the bottom diagram turns into a schmitt trigger circuit as the top diagram. From other schmitt trigger circuits I have see on yout...


AoE 3rd Ed heavy discount on Amazon UK

Started by Adrian Caspersz in sci.electronics.basics2 months ago 9 replies

A UK heads up, https://www.amazon.co.uk/Art-Electronics-Paul-Horowitz/dp/0521809266 Hardcover, sold direct from Amazon, £23.50 You...

A UK heads up, https://www.amazon.co.uk/Art-Electronics-Paul-Horowitz/dp/0521809266 Hardcover, sold direct from Amazon, £23.50 You Save: £42.49 (64%) I had the first edition at college, and sold it on to a new student. Second edition came out, I was still broke so hunted down an old first on eBay. For me third edition now on the way :) BTW The companion "Learning the Art ...


Measuring Accuracy: 1.0 grade

Started by Bob Engelhardt in sci.electronics.basics2 months ago 3 replies

An Amazon meter is described as having "Measuring Accuracy: 1.0 grade". I found that there is a standard that defines the grades, but is there a...

An Amazon meter is described as having "Measuring Accuracy: 1.0 grade". I found that there is a standard that defines the grades, but is there a simple answer to what "1.0 grade" means in percentage? (I know how difficult it can be to extract simple answers from standards.)


Retro Button Would Further Automation On the Boeing Max & Everything Else That Seems Sophisticated Beyond the Intelligence of Designers

Started by Bret Cahill in sci.electronics.basics2 months ago 51 replies

Put a retro or "my kingdom for a horse" switch on anything that seems unnecessarily over automated or when the additional sophistication is of a...

Put a retro or "my kingdom for a horse" switch on anything that seems unnecessarily over automated or when the additional sophistication is of a minor advantage. If anything doesn't seem perfect, tap the retro switch and you are back to flying by the seat of your pants or at least something that is less complicated / more proven technology. It may seem counter intuitive but this would actual...


Failure mode of LEDs in overcurrent situation

Started by Andrew T. in sci.electronics.basics2 months ago 3 replies

I'm curious about what happens to an LED when it is exposed to a moderate overcurrent situation. This question came about as I was...

I'm curious about what happens to an LED when it is exposed to a moderate overcurrent situation. This question came about as I was troubleshooting some small white LED lights I built using 3 5mm LEDs and a current limiting resistor to run on 12Vdc (supplied by a lead-acid battery charged by solar). After some time, many of these strings would start to flicker or blink. I was about to po...


Basic circuit help please

Started by RobH in sci.electronics.basics2 months ago 66 replies

I have put together a circuit from here: https://circuitdigest.com/electronic-circuits/light-fence-circuit-diagram-with-alarm and this is the...

I have put together a circuit from here: https://circuitdigest.com/electronic-circuits/light-fence-circuit-diagram-with-alarm and this is the schematic: https://circuitdigest.com/fullimage?i=circuitdiagram/Automatic-Light-Fence-Circuit-Diagram-with- Alarm.png I have the led, ldr and the 100k pot part of the circuit working fine, but the buzzer from the 555ic does not work or sound as it i


I load BTC wallet. NO UPFRONT FEE! This is a real deal.

Started by Anonymous in sci.electronics.basics2 months ago

I load BTC wallets, Recover lost Bitcoins, & help with FOREX / BITCOINS Investments. For more info text or send me a message via whatsApp -  +1...

I load BTC wallets, Recover lost Bitcoins, & help with FOREX / BITCOINS Investments. For more info text or send me a message via whatsApp -  +1 (772) 361 1184   I am Yang Joshua Administrator at Block Chain


Wattage of rough service incandecent bulbs ??

Started by Steve Wolf in sci.electronics.basics2 months ago 48 replies

I have build a series load test light. eg. you plug a load in and it runs in series through a lamp, in case there is a short, the lamp takes up...

I have build a series load test light. eg. you plug a load in and it runs in series through a lamp, in case there is a short, the lamp takes up the load, so as to not blow a fuse. The lamp you use should be 3 x's the load. eg 20 watt load should have a 60 watt bulb. this means that you really need a variety of lamps. Once finished I realized that getting an incandescent light bulb i


Engineer's Mini Notebook Series is on-line

Started by default in sci.electronics.basics2 months ago

https://archive.org/search.php?query=Forrest%20Mims%20engineer%27s%20mini-notebook

https://archive.org/search.php?query=Forrest%20Mims%20engineer%27s%20mini-notebook


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