OT-Electronics and Warts

[Anonymous-0]

Got tired of havin Wall-wart transformers in every drawer and cranny I open,every box or bin or coffee can I want to use,so today we had a roundup of the varmints and corraled all the mavericks,bout 30+,in one bucket.Voltages range from 1.5 to 35.Heres the problem.I know that ea normal AAAs/AAs/Cs/Ds are nominally 1.5V and basic math says that 2=3V/3=4.5V/4-6V/etc.I would like to mark these transformers w/understandable references so that others might benefit from them.In short do the milliamp outputs of the warts,equal output of batteries,as in 3VDC,200ma/=to 2 AAAs?,2-AAs?.There has to be a point of reference,so one knows that say,a 500ma Wart will replace 2-D cells w/o overloading etc.....Any input?

 

[Anonymous-0]

Remember, I = V/R or the current draw equals the voltage divided by the resistance. In the case of your DC power supply, the current rating on the unit is the maximum current draw you can take and keep the voltage constant.

Batteries on the other hand, will degrade in output voltage during usage.

Thus, you can use your DC power supplies where:
a) the voltage output matches the input voltage of the device you are trying to power
b) the device current draw is less than the output current rating on the DC Power Supply.

 

[Anonymous-0]

OK,that is simple enough,but from"the other emd",if I have a radio,that requires 4-D cells or(6VDC),then how many milliamps minimum do I need to supply to it?I do know if voltage is correct,it will only consume what it needs,so over-powering it amperagewise is not an issue.Sadly most electronics give an AC consumption rate,but for DC simply say like"4-D cells or equivalent or AAAx2.

 

[John T]

Just knowing what voltage the radio uses (2, 4 or 6 batteries etc) DOES NOT TELL YOU HOW MANY MILLIAMPS ITS GONNA DRAW. However, on a typical small garden variety battery powered transistor radio, many of the lil transformer power supplies Ive seen are likely big enough to supply the radios needed amperage as any battery powered device cant be drawing very high amperage to begin with. If not, you will notice poor or non performance cuz the volatge is dropped down and/or you might let the smoke out of the transformer grrrrrrrrrrrrrr.

You have to know the amperage draw of the radio (or watts n do the math) to accurately size a power supply but that info may not be available. If you have those power supplies laying around collecting dust Id just use ones of the appropriate voltage (and you do know that) and theres a good chance they will suffice, but if not trash them out

BUTTTTTTT CAUTION if unsure I wouldnt let one be on any easily combustible surface in case it overheats and would watch n monitor its heat a while before I plugged it in n forgot about it.

John T

 

[MLP]

Unregulated wall warts are designed to work at a specific load. If the load is too light then the out put voltage will be too high. For example a 9VDC 500ma wart may be putting out 16VDC at a 50ma load. I some times use them this way when it is a none critical application. A regulated wall wart will hold the voltage fairly constant up to it’s current rating.

 

[Anonymous-0]

GASP! What is this"throw away"people speak of? Are you not just supposed to keep eveything and just buy a bigger house or another freight container every few yrs?That way your heirs can have a HUGE estate sale someday

If only they were more easily recyclable..the copper windings inside are prolly worth more'n the warts these days...awhile back a had a 3lb coffee can fulla various bits of clean copper wire and other little copper bits...bout fainted when the scrap guy said "6 bucks".

 

[Lou NY]

While you do know the voltage of the power-supplys from there tags, and the output power from the mA ratings, You will also find a multitude of different tip sizes and configurations, some may have the + on the tip, some will have the - there, some will be hollow and different polarities inside to outside, have fun.
Lou

 

[souNdguy]

Unfortunately.. if it is an unregulated power supply, as mentioned. the voltage will not be constant.. but is instead 'rated, at that current load. IE.. if your load is much less, then the voltage may be higher, depending on design characteristics.. etc.

See if there are wattages listed.. run them thru e=IR and get a real rough baseline for comparison for loading those wall warts.. etc.

Soundguy

 

[Anonymous-0]

why not put a ampmeter in series with the batterys on your project and measure the actual draw ?