How to tell speaker + from -?

Started by Anonymous in sci.electronics.basics1 month ago 12 replies

In my shop I have a a Pioneer SX-434 radio/amp for my listening pleasure. The speakers are mounted high up, screwed to the wall, and are not...

In my shop I have a a Pioneer SX-434 radio/amp for my listening pleasure. The speakers are mounted high up, screwed to the wall, and are not easy to get at. I had to disconnect the speaker wires temporarily from the stereo and stupidly didn't mark the wires for positive and negative. Is there a way to tell which wires are which that doesn't involve ladders and me unscrewing the speakers from...


Cell phone fast charging circuits

Started by Anonymous in sci.electronics.basics2 months ago 6 replies

Hello, My Motorola phone supports "Turbo" charging, apparently charging my phone at 9-12V after establishing a secret handshake with the...

Hello, My Motorola phone supports "Turbo" charging, apparently charging my phone at 9-12V after establishing a secret handshake with the charger. https://www.motorola.com/us/products/turbopower Is there a chip that performs this authentication? I'd like to build a car charger for my phone without blowing it up, but I haven't seen any sample schematics. All I've seen is a reference t...


Oscillators without transistors

Started by Anonymous in sci.electronics.basics2 months ago 24 replies

Hello, What are some examples of oscillators which don't require transistors or vacuum tubes? So far I found relay oscillators and the...

Hello, What are some examples of oscillators which don't require transistors or vacuum tubes? So far I found relay oscillators and the Pearson-Anson oscillator. Does the Pearson-Anson oscillator require a high-voltage neon lamp, or would it work on LEDs as well? https://en.wikipedia.org/wiki/Pearson%E2%80%93Anson_effect Relay oscillators look neat too but I don't imagine they would la...


Speaker efficiency?

Started by Anonymous in sci.electronics.basics3 months ago 12 replies

Since I will be playing a low wattage tube amp through speakers it seems that high efficiency speakers are in order. How can I tell...

Since I will be playing a low wattage tube amp through speakers it seems that high efficiency speakers are in order. How can I tell the efficiency of a speaker from looking at the specs? Thanks, Eric


Serious stereo tube amp questions.

Started by Anonymous in sci.electronics.basics3 months ago 8 replies

I have always like exposed tube equipment. Since I was a little kid. So I have been thinking about getting a small stereo tube amp for the...

I have always like exposed tube equipment. Since I was a little kid. So I have been thinking about getting a small stereo tube amp for the living room to replace the typical modern amp we have. That no longer works. All the modern small amps have outputs of several tens of watts. But all of the small tube amps I see and remember only have outputs of less than ten watts. Is there someth...


solar cell how to measure output current

Started by Anonymous in sci.electronics.basics3 months ago 13 replies

Hi - I got a brand new solar cell "Eco Line ES10M36". In my garden, under full sun it provides 21 volts and 500 mA, and under big shadow it...

Hi - I got a brand new solar cell "Eco Line ES10M36". In my garden, under full sun it provides 21 volts and 500 mA, and under big shadow it gives 18 volts and 30 mA. Load is a 24 volt bulb lamp in series with the Fluke. As the voltage margin is small, I want to detect the intensity to determine if there is sun or not. What electronic circuit would you recommend to do it ? If I pl...


tool to use to draw an electronic circuit

Started by Sebastia RodaMon in sci.electronics.basics3 months ago 7 replies

Hi - if I want to show you an electronic circuit I have a question about, what tool do you recomend me to use ? Thanks.

Hi - if I want to show you an electronic circuit I have a question about, what tool do you recomend me to use ? Thanks.


Tube amp question

Started by Anonymous in sci.electronics.basics3 months ago 14 replies

I see lots of tube amps with the tubes mounted such that they point down. This means all the heat rises up into the chassis. This...

I see lots of tube amps with the tubes mounted such that they point down. This means all the heat rises up into the chassis. This seems counter-intuitive to me. All those components baking all the time. Is it just for convenience? Eric


Single phase VFD-nevermind

Started by Anonymous in sci.electronics.basics4 months ago 9 replies

Last time I looked, which was several years ago and for a different reason, I found nothing. Today I found them and they are cheap. I shoulda...

Last time I looked, which was several years ago and for a different reason, I found nothing. Today I found them and they are cheap. I shoulda looked before posting. Sorry, Eric


The Tesla Spirit Radio - Full Spirit Communication Test

Started by Mr. Man-wai Chang in sci.electronics.basics4 months ago 6 replies

The Tesla Spirit Radio - Full Spirit Communication Test -- @~@ Remain silent! Drink, Blink, Stretch! Live long and prosper!! ...

The Tesla Spirit Radio - Full Spirit Communication Test -- @~@ Remain silent! Drink, Blink, Stretch! Live long and prosper!! / v \ Simplicity is Beauty! /( _ )\ May the Force and farces be with you! ^ ^ (x86_64 Ubuntu 9.10) Linux 2.6.39.3 ???! ???! ???! ???! ???! ???! ???! ???!


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