MOSFET switch - sanity check

Started by Bob Engelhardt in sci.electronics.basics15 hours ago 7 replies

I have a Milwaukee 12v variable speed tool with a bad control board. Rather than replace the board, I'm planning to just use a switch for...

I have a Milwaukee 12v variable speed tool with a bad control board. Rather than replace the board, I'm planning to just use a switch for single (full) speed. But the switches that I have & will fit are AC only. So, I'm thinking that I'll use the switch to control a MOSFET that will do the heavy lifting. I just want to make sure that I'm not missing anything. The plan: + ______...


VOX- Voice operated Relay with mods.

Started by amdx in sci.electronics.basics3 days ago 2 replies

I'm starting to develop a VOX circuit to solve the following problem. Wife got new smart phone after flip phone went in water. We're on a...

I'm starting to develop a VOX circuit to solve the following problem. Wife got new smart phone after flip phone went in water. We're on a boat. Wife's phone is inside now, she's outside working, can't hear the phone ring. Won't take the phone outside, I think she thinks she paid $0.01 for the flip phone and $200 for the smart phone and won't take a chance with it. So I want to build ...


Short +ve pulses, simplest solution?

Started by Terry Pinnell in sci.electronics.basics3 days ago 9 replies

The curtain controller I made about 12 years ago toggles the curtains to open or close on pressing a momentary push button. For holidays...

The curtain controller I made about 12 years ago toggles the curtains to open or close on pressing a momentary push button. For holidays I improvised a circuit based on an LDR inside one of those old mechanical mains-operated timers. The LDR is flush up against its neon light. That part of my circuit has recently stopped working and I've started work on it. But meanwhile I'd welcome suggestio...


Transformerless Power Supply

Started by amdx in sci.electronics.basics1 week ago 8 replies

Is it reasonable/possible to build an 8 amp 20 V transformerless power supply from a 120Vac line. I calculate about 180uf plus or minus...

Is it reasonable/possible to build an 8 amp 20 V transformerless power supply from a 120Vac line. I calculate about 180uf plus or minus depending on other components. Maybe 9- 20uf caps in parallel? I'd like to build it into a leaf blower. All plastic, absolutely no metal exposed. I think I've answered my question, I have 12, X rated caps in my junk box, but they are only...


Transformerless power supply

Started by amdx in sci.electronics.basics1 week ago

Is it reasonable/possible to build an 8 amp 20 V transformerless power supply from a 120Vac line. I calculate about 180uf plus or minus...

Is it reasonable/possible to build an 8 amp 20 V transformerless power supply from a 120Vac line. I calculate about 180uf plus or minus depending on other components. Maybe 9- 20uf caps in parallel? I'd like to build it into a leaf blower. All plastic, absolutely no metal exposed. I think I've answered my question, I have 12, X rated caps in my junk box, but they are only 1uf....


Is Class 1 laser safe enough for baby eyes?

Started by Mr. Man-wai Chang in sci.electronics.basics2 weeks ago 11 replies

I meant, what if someone accidentally shine Class 1 laser into a baby's eyes? Would it hurt retina and leave a permanent damage? I know ......

I meant, what if someone accidentally shine Class 1 laser into a baby's eyes? Would it hurt retina and leave a permanent damage? I know ... I know... it should NOT happen. Adults are supposed to be very very careful. :) -- @~@ Remain silent! Drink, Blink, Stretch! Live long and prosper!! / v \ Simplicity is Beauty! /( _ )\ May the Force and farces be with you! ^ ^ (x8...


Formula for calculating run time of apc ?

Started by Andy in sci.electronics.basics3 weeks ago 3 replies

I am looking for a formula for calculating the run time of my APC battery system. I did a search but what I found required a particular model...

I am looking for a formula for calculating the run time of my APC battery system. I did a search but what I found required a particular model of apc. Total watts of computer and monitor is about 120 watts. Battery in my apc is 12V 18 Ah Thanks, Andy


[BBC] Einstein theory passes black hole test

Started by Mr. Man-wai Chang in sci.electronics.basics3 weeks ago 1 reply

[BBC]Einstein theory passes black hole test Full story: https://www.bbc.com/news/science-environment-44967491 The black hole at the centre of...

[BBC]Einstein theory passes black hole test Full story: https://www.bbc.com/news/science-environment-44967491 The black hole at the centre of our galaxy has helped astronomers confirm a key prediction of Albert Einstein's ideas. By observing a cluster of stars near the hole, they were able to confirm a phenomenon known as "gravitational redshift". It's when the wavelength of light ge...


Update: Varistor/MOV Spice Modeling

Started by Jim Thompson in sci.electronics.basics4 weeks ago 30 replies

Varistor/MOV Spice Modeling has been updated. See VaristorMOV.zip on the Device Models & Subcircuits Page of my website. ...

Varistor/MOV Spice Modeling has been updated. See VaristorMOV.zip on the Device Models & Subcircuits Page of my website. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Sa...


three terminal volt regulator

Started by George Herold in sci.electronics.basics4 weeks ago 11 replies

Hi all, Simple question. Some 1/2 amp LM7805 is obselete (TO-220 pac) I need a replacement. So either a 1 amp...

Hi all, Simple question. Some 1/2 amp LM7805 is obselete (TO-220 pac) I need a replacement. So either a 1 amp 7805 http://www.onsemi.com/pub/Collateral/MC7800-D.PDF or a LM340 http://www.ti.com/lit/ds/symlink/lm340.pdf Is there any (practical) difference between the two? (besides the price.) George H.


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