Adjustable Dimmer: Newsletter Challenge (12/06/05)

use the junk wire and wrap it on the iron stalk put it in line with the light and by moving the stalk in and out it should act as a dimmer for the light

Turn down the bet, because you don't want him shocking himself or burning his fingers if the stock gets hot. Then help him to do it safely using the metal stock as an inductor core and some of the fasteners to fix the core in place. You can then dim the light by wrap some of the wire around the (now fixed) stock. It's more than two items, but it's worth it to see him go safely off to school tomorrow.

get a bucket of water. Put 2 wires apart in the water. Move one up and down to vary the contact resistance with the water, and voila': you have made a power variable resistor. I did this as a kid to "start" an arc without tripping the breaker. sr

Safety first and Ocum's Razor. Sure you could use the wire to make a variable inductor and hack up a perfectly good lamp cord or make some "bailing wire" cludge to patch it in the AC line but hey, why go to all that trouble? Just wrap the wire around the lamp housing. Now you can adjust the spacing of the wire to create a variable aperature and you don't have to mess with the AC hazard and all the ensuing difficulties.

Sort through your "recovered pieces of old electronic stuff" bin and pull out a nice silicon power diode of, say, 200V/1A rating or so. Secure it in one line of your extension cord and the lamp may only reach about half brightness...and 'bonus' - the lamp will last a lot longer as well... ;) but that's assuming you go the high tech route. If you want to get fancy, wrapping that first bit of wire around the iron stock will certainly give you a hefty coil, but it would be neat to wrap the lamp wire around a leftover piece of PVC and slide that plugged-in coil inside of it for an induction dimmer!

Easy way to fix the problem. Find an old tin can that is usually full of nuts and other odd stuff. Take the tin and cut the bottom out of it. Then take the can and place it over the lamp housing. this will make the light shine directly where you want it in about a 3 inch circle so you can see clearly. Call it a glorified flashlight. To make the light brighter and cover more space slide the tin can back on the light.

You could adjust the current by using a variable resistor in serie with the lamp cord. What I did when I was a kid, with a low power lamp, was using the grafite of wood pencil, wrapping the wires around the grafite so I could adjust the resistance. Any low conductance material would make the trick.

The kid took a physics course -- he is not going to have any practical knowledge about anything. However one thing he should know is that the intensity of the lit surface is a function of the square of the distance from the light source. Simply moving the light closer or further will vary the light intensity. However there will probably be difficulty in getting the light where it is needed due to obstructions, therefore some type of reflector may be needed to direct the light. A piece of white cardboard taped to fold out ruler would do.

I know this is only for fun, but if the light was to bright in the first place ??? why did you ask your son to hold it so you could see better. Im sure you could have thought of a better example for the question than that...Don't you think..??

i agree with the last guy if it's too bright in the first place why use it but if it's the only one you have maybe next time have him grab you your sunglasses off the dash in your car for you first before holding the light for you :o)

Absolutely take this bet! The basic plan is to make a transformer out of the steel barstock and wire. Take the barstock and wrap 100 turns of wire for the primary. Then wrap another coil of 100 turns around the barstock next to the primary and you have a secondary coil. The two ends of the primary wire are hooked up to a zip cord with a 120 volt plug. Same thing for the secondary except that there is a receptacle for output voltage. To reduce the output voltage, take turns off the secondary until the lamp plugged into the secondary is dimmed to the desired level. Fasteners could be used to create secondary taps so that the wire wouldn't need to be unwrapped, but I prefer the minimalist solution.

Mr. Bean raises his eyebrow and index finger up and puts on that devilish grin. What has Mr. Bean got in mind this time?

Mr. Bean drops his head into his junk box and pulls out a rat's nest of wire and immediately begins wrapping the wire around the light bulb until the bulb is partly obscured by the wire windings. Presto! A mechanical dimmer has been created.

Unfortunately, Mr. Bean is left with an excess of wire dangling all over the place. Errr… Ahh! Mr. Bean grabs the steel bar and smashes it against the excess ends of the wire lying on the cement floor. Once again, Mr. Bean reigns with lateral thinking.

you hopefully have a good battery in the car. If so you can build a magnetic amplifier using the extension chord and iron bar to wind the power section and the car battery and wire scraps to wind the control circuit. If not you could wind a transformer or reactor but I wouldn't let my son do these because of dangers of electric shock.

Del ???????