How to get 1.5 volts out of a wall-wart power supply's 3 volt output...I am new to this group I believe anyways...Nice to meet you all!

Started by Daniel in sci.electronics.basics9 years ago 19 replies

Hi, I have recently been trying to get 1.5 volts (or anything other than th= e power supply's rated 3 volts for that matter) out of a wall-wart 3...

Hi, I have recently been trying to get 1.5 volts (or anything other than th= e power supply's rated 3 volts for that matter) out of a wall-wart 3 volt p= ower supply. The wall-wart power supply is dc in output at 3 volts and even= if I connect a 300 ohm resistor in series with the wall-wart power supply = and the load (a 1.5 volt clock, old style analog clock)and when i measure t= he voltage...


Air Purifier UV Bulbs

Started by Bret Cahill in sci.electronics.basics9 years ago 2 replies

Are air purifier UV bulbs 120 V AC or do they need some kind of power supply? http://www.iallergy.com/product_info.php?products_id=678

Are air purifier UV bulbs 120 V AC or do they need some kind of power supply? http://www.iallergy.com/product_info.php?products_id=678


DC 17V from PC power supply?

Started by Mr. Man-wai Chang in sci.electronics.basics9 years ago 22 replies

1. If I shorted the +5V and +12V in the molex connector, would I get +17V? What's the max. current? 2. Could I use 17V to charge a...

1. If I shorted the +5V and +12V in the molex connector, would I get +17V? What's the max. current? 2. Could I use 17V to charge a notebook battery rated 16V and 3.8A? Would it hurt the battery? -- @~@ Remain silent. Nothing from soldiers and magicians is real! / v \ Simplicity is Beauty! May the Force and farces be with you! /( _ )\ (Fedora 18 i686) Linux 3.9.6-200....


Very interesting 'scoping results

Started by Anonymous in sci.electronics.basics9 years ago 10 replies

At least interesting to me. On the advice from members of this newsgroup I bought a 465B TEK oscilloscope. It comes in handy now and then....

At least interesting to me. On the advice from members of this newsgroup I bought a 465B TEK oscilloscope. It comes in handy now and then. Yesterday I had to replace a power supply in one of my CNC machines. The only one available in a reasonable length of time was a used one of unknown quality. I spoke to a friend of mine and he said to 'scope the thing and look for any ripple on the DC out...


Section about switching mode power supply just started

Started by Patrick Chung in sci.electronics.basics9 years ago 2 replies

http://www.cirvirlab.com/index.php/switching-mode-power-supply.html Read first...

http://www.cirvirlab.com/index.php/switching-mode-power-supply.html Read first article: http://www.cirvirlab.com/index.php/switching-mode-power-supply/129-buck-or-step-down-converter-b asics.html


Buck DC-DC converter online simulation

Started by Patrick Chung in sci.electronics.basics9 years ago

Online simulation of buck (step-down) DC-DC converter is ready. http://www.cirvirlab.com/simulation/smps_buck_converter_online.php Read...

Online simulation of buck (step-down) DC-DC converter is ready. http://www.cirvirlab.com/simulation/smps_buck_converter_online.php Read theory of operation: http://www.cirvirlab.com/index.php/switching-mode-power-supply/129-buck-or-step-down-converter-b asics.html


Flyback converter

Started by Patrick Chung in sci.electronics.basics8 years ago

Even though some authors presents flyback converter as transformer isolated boost converter, it is more closer to reality that flyback dc-dc...

Even though some authors presents flyback converter as transformer isolated boost converter, it is more closer to reality that flyback dc-dc converter can be explained as transformer isolated buck-boost converter. Read more: http://www.cirvirlab.com/index.php/switching-mode-power-supply/132-flyback-dc-dc-converter-basic s.html Also, simulate flyback converter online on http://www.cirvirl


Forward converter is actually transformer isolated buck (step down) converter.

Started by Patrick Chung in sci.electronics.basics8 years ago

Read more: http://www.cirvirlab.com/index.php/switching-mode-power-supply/143-forward-dc-dc-converter-basic s.html Also, simulate forward...

Read more: http://www.cirvirlab.com/index.php/switching-mode-power-supply/143-forward-dc-dc-converter-basic s.html Also, simulate forward converter online on http://www.cirvirlab.com/simulation/smps_forward_dc_dc_converter_online.php


Benchtop Power Supply Options

Started by Jurd in sci.electronics.basics8 years ago 88 replies

Hello again, It is time for me to acquire a better bench top power solution. Most of the time I will use it to power a breadboard for...

Hello again, It is time for me to acquire a better bench top power solution. Most of the time I will use it to power a breadboard for experimentation. I used a wall wart for awhile until it got super noisy, and batteries are a hassle. I was about to go for something like this: http://tinyurl.com/qexphfy And then attach something like this: http://tinyurl.com/qc5e9ma to the leads ...


Any Oldtimers Want To Play "What Is This THing ?"

Started by Anonymous in sci.electronics.basics8 years ago 8 replies

Here's one of those old things you just pick up because it's old.=20 It is a "portable test oscillator". That much is no mystery, but that's...

Here's one of those old things you just pick up because it's old.=20 It is a "portable test oscillator". That much is no mystery, but that's abo= ut it.=20 https://dl.dropboxusercontent.com/u/29948706/DSCN0398.jpg So I dig up a 90 volt power supply, actually by taking an old amp carcass a= nd connecting between the positive and negative rails. A variac got it to t= he level I wanted. I...


low-power audio amp basics

Started by Anonymous in sci.electronics.basics8 years ago 14 replies

For some low-power audio amps, usually less than 2 Watts, I see the amplifier powered by +V...

For some low-power audio amps, usually less than 2 Watts, I see the amplifier powered by +V and ground: http://www.redcircuits.com/Page33.htm For other, usually higher-powered amplifiers, I see a +/- power supply required. http://www.redcircuits.com/Page164.htm Do the amplifiers without a +/- supply continuously provide a voltage at 1/2 V during the silent parts, to allow the speaker room ...


ATX kludge

Started by Stumpy in sci.electronics.basics8 years ago 11 replies

I will be visiting Fry's electronics or Radio Shack on Tuesday. Need to make a list of parts to use an old ATX power supply for 12V cigarette...

I will be visiting Fry's electronics or Radio Shack on Tuesday. Need to make a list of parts to use an old ATX power supply for 12V cigarette lighter projects. http://www.frys.com/product/6269850?site=sr:SEARCH:MAIN_RSLT_PG http://www.frys.com/product/1916056?site=sr:SEARCH:MAIN_RSLT_PG http://www.frys.com/product/472305?site=sr:SEARCH:MAIN_RSLT_PG http://www.frys.com/product/2860...


Current mode control

Started by Patrick Chung in sci.electronics.basics8 years ago

Current mode control is the fastest control method for switching mode power supply since it has to feedback loops. Read...

Current mode control is the fastest control method for switching mode power supply since it has to feedback loops. Read more: http://www.cirvirlab.com/index.php/switching-mode-power-supply/152-current-mode-control-or-curre nt-programming-regulating-scheme.html


Voltage mode control and One cycle control

Started by Patrick Chung in sci.electronics.basics8 years ago 1 reply

Voltage mode control is not as fast as current mode control, but it is applicable in wider load range. One cycle control if further improvement...

Voltage mode control is not as fast as current mode control, but it is applicable in wider load range. One cycle control if further improvement of voltage mode control. Read more. http://www.cirvirlab.com/index.php/switching-mode-power-supply/157-voltage-mode-control-and-one- cycle-control.html


Power factor correction circuits

Started by Patrick Chung in sci.electronics.basics8 years ago

Power factor correction circuits are essential part of modern household power supplies. These circuit have a feature of behaving almost as a pure...

Power factor correction circuits are essential part of modern household power supplies. These circuit have a feature of behaving almost as a pure resistive load to the power network, and obtaining DC with sine ripple on the output. Read more. http://www.cirvirlab.com/index.php/switching-mode-power-supply/164-pfc-power-factor-corrector-ci rcuit.html


Automotive relay question

Started by DaveC in sci.electronics.basics8 years ago 15 replies

I have a 12V SPST cube relay in my junque box. The diagram molded into the relay?s housing includes a component connected in parallel with the...

I have a 12V SPST cube relay in my junque box. The diagram molded into the relay?s housing includes a component connected in parallel with the coil which looks suspiciously like a resistor. It?s not a back-emf diode: I connected the relay coil using both polarities (using a current-limited power supply) and the same current draw is measured. What is the purpose of this resistor? ...


Automotive relay question

Started by DaveC in sci.electronics.basics8 years ago 2 replies

I have a 12V SPST cube relay in my junque box. The diagram molded into the relay?s housing includes a component connected in parallel with the...

I have a 12V SPST cube relay in my junque box. The diagram molded into the relay?s housing includes a component connected in parallel with the coil which looks suspiciously like a resistor. It?s not a back-emf diode: I connected the relay coil using both polarities (using a current-limited power supply) and the same current draw is measured. What is the purpose of this resistor? ...


Power supply current?

Started by Peter Percival in sci.electronics.basics2 years ago 24 replies

I wish to buy a power supply delivering up to 500V for experiments with thermionic valves. What would be a suitable current?

I wish to buy a power supply delivering up to 500V for experiments with thermionic valves. What would be a suitable current?


Capacitor as a power supply

Started by M. Hamed in sci.electronics.basics7 years ago 9 replies

This is more of a thought experiment triggered by handling of a huge cap. Would it be possible to charge a big cap and discharge it through a load...

This is more of a thought experiment triggered by handling of a huge cap. Would it be possible to charge a big cap and discharge it through a load resistor without dropping voltage much over a significant portion of the discharge time? One way I could think of is to use a Zener followed by an emitter follower to act like a current source. However the Zener needs a load resistor and non-zero cu...


DC-DC converters basic topologies online simulations

Started by Patrick Chung in sci.electronics.basics8 years ago

DC-DC converters are essential power supply circuits for modern electronic equipment today. Five basic topologies are ready now for online...

DC-DC converters are essential power supply circuits for modern electronic equipment today. Five basic topologies are ready now for online simulation. Visit them on: http://www.cirvirlab.com/index.php/tutorials/168-dc-dc-converters-online-simulator.html