"momwithtools" wrote in message
lkaboutelectronicequipment
..com...
For an elementary school project, I'd like the children to take apart some
old electronics to get an idea of how things work, what goes into each
product, etc. My question is: Are there certain electronics or appliances
we should stay away from because of chemicals or something else that would
be unsafe for the children? Please advise.
Thank you!
Mom With Tools


One of my electronic hints on
http://homepages.tcp.co.uk/~diverse
is the following , most safety factors covered but I'm sure there
are more eg kid with hacksaw sawing into a power
transistor and eating the Beryllium Oxide as Sherbert Lemon

Something to keep a kid occupied on a wet weekend
Obtain a dumped VCR (older the better) and get little Johny to take apart
to the last screw and washer.
Safety note cut off the mains lead should he think of powering up,
powerful magnets inside so could nip fingers also sometimes
strong springs that need to be released carefully and some
screws and circlips may be beyond strength or dexterity of a kid.
Interesting bits to be found inside that can be instructively re-used.
Motors and solenoids usually about 12V,pulleys,belts and cogs.
Often a compact reduction gear train attached to one motor.
Infra-red LED transmitter and reciver.
Dew sensor (humidity) usually Aluminium plate screwed onto the base
of the video head assembly - holding usually white ceramic with dark grey
square on it or green epoxy lump with 2 wires coming from it.
Put on a DVM and breath on it.
Inside the capstan motor often 3 Hall effect sensors that would
need desoldering. Put about 5V on the pins that were paralleled
together on the pcb. Or find pair of pins with DVM diode
test with low forward drop in either direction to find the
power pins (assuming 4 pin variety). Monitor the voltage
between the other 2 pins with moving magnet.
Observe the video heads under a kids microscope and imagine
how those turns of fine wire are looped through that tiny hole.
Count all the bits and pieces that make up a VCR