LED RF Noise Evaluation

Started by ABLE1 in sci.electronics.basics1 year ago 8 replies

Hello, I have experienced what seems to be RF Noise that is generated from LED lighting. I don't have the exact spec's but just...

Hello, I have experienced what seems to be RF Noise that is generated from LED lighting. I don't have the exact spec's but just wondering if anyone here knows of what to look for as to packaging labels or spec's on LED lighting, if any. The issue just came up today when talking to a customer that has just recently had LED lights in there bar. He says now there is noise that is being ...


12 Vdc led running hot

Started by AK in sci.electronics.basics1 year ago 11 replies

I bought some 12 VDC 5 mm red leds. They work find but... when I touch the wires going into the led, they were hot enough that I had to...

I bought some 12 VDC 5 mm red leds. They work find but... when I touch the wires going into the led, they were hot enough that I had to remove my hand. That does not seem normal. Thanks.


Independence of Capacitance from Dielectric

Started by Hamid V. Ansari in sci.electronics.basics1 year ago 2 replies

Hi, A simple carelessness has caused the famous formula for the electrostatic potential to be written wrongly while in its correct form we must...

Hi, A simple carelessness has caused the famous formula for the electrostatic potential to be written wrongly while in its correct form we must use a term showing electrostatic field arising only from the external charges not also from the polarization charges. So, capacitance of a capacitor does not at all depend on the dielectric used in it and depends only on the configuration o


Anyone with plc experience?

Started by default in sci.electronics.basics1 year ago 5 replies

I was looking for a ready made timer for a hydroponic system I'm tinkering with and came across some el-cheapo PLCs on Amazon, and figured this...

I was looking for a ready made timer for a hydroponic system I'm tinkering with and came across some el-cheapo PLCs on Amazon, and figured this would work lots better than a timer that would need a lot of additional circuitry to adapt. The catch is that they mention a programming software that is from Mitsubishi and costs $500+ . After looking around I found some cheaper alternatives but ...


Frequency counter

Started by Peter Percival in sci.electronics.basics1 year ago 29 replies

I'd like to buy a frequency counter but I was afraid they'd cost thousands. Apparently, "only" hundreds -...

I'd like to buy a frequency counter but I was afraid they'd cost thousands. Apparently, "only" hundreds - https://uk.rs-online.com/web/p/products/6654919/?tpr=2. Any recommendations? -- "He who will not reason is a bigot; he who cannot is a fool; he who dares not is a slave." - Sir William Drummond


Will this work safely?

Started by Terry Pinnell in sci.electronics.basics1 year ago 10 replies

Pressing the door button of my commercial wireless door bell causes the mains-powered speaker unit in the hall to chime. Rather than buying...

Pressing the door button of my commercial wireless door bell causes the mains-powered speaker unit in the hall to chime. Rather than buying another speaker unit I thought I'd make a simple extension myself. I'd then get an identical chime in my workshop. With difficulty I was able to get access inside the unit and connected a couple of wires in parallel with its tiny speaker, like this: ...


GFCI/lightening

Started by default in sci.electronics.basics1 year ago 2 replies

I had a lightning strike hit an antenna mast and it took out a lot of electronics in my house. It actually popped circuit breakers in the house...

I had a lightning strike hit an antenna mast and it took out a lot of electronics in my house. It actually popped circuit breakers in the house along with taking out the TV, modem, KVR switch, low voltage LED lighting, and several power supplies. The interesting thing was the circuit for the Ground Fault outlet that feeds my outdoor workbench was kaput, but didn't show any signs of being ...


Inductance calculations

Started by Peter Percival in sci.electronics.basics1 year ago 5 replies

Somewhere there must be a formula for the inductance of a hand-wound coil. Air core, one layer of wire (of given swg) close-wound, diameter of...

Somewhere there must be a formula for the inductance of a hand-wound coil. Air core, one layer of wire (of given swg) close-wound, diameter of former (cardboard, probably inside of toilet paper roll), length of coil,... (what else?), therefore inductance equals ...


Two diode vs four diode rectification

Started by Peter Percival in sci.electronics.basics1 year ago 31 replies

What is the advantage of a four diode bridge full-wave rectifier over a two diode full-wave rectifier. There must be some, else why accept the...

What is the advantage of a four diode bridge full-wave rectifier over a two diode full-wave rectifier. There must be some, else why accept the extra cost? -- "He who will not reason is a bigot; he who cannot is a fool; he who dares not is a slave." - Sir William Drummond


Current vs. wire gauge

Started by Peter Percival in sci.electronics.basics1 year ago 7 replies

What current can 18AWG wire carry? And, more usefully, is there a table somewhere giving this info for all the usual gauges?

What current can 18AWG wire carry? And, more usefully, is there a table somewhere giving this info for all the usual gauges?


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