Exposed over door contact

[Geordie Spark]

A level physics. 1985. Top teacher (ex RAF engineer). Demo'd this beautifully.

he rigged up a...well a rig at the front with thousands of windings versus well, two or three about a centimetre thick (or a centimeter if you're American) with huge clamps either end. Got a monster nail out (all to prove the amps point), asked what we thought would happen etc, then clamped the nail betwixt the ...clamps and powered up. By the way ( can't put btw it just feels wrong!!!!!) this was way before H&SE gone mad but he had a huge perspex shield for the class of grunty 17 year olds and he was wearing a mask

massive bang, nail literally exploded ( as Im sure you expected). Them were the days "ay it" still remember watching the chemistry teacher whimper and panic because he'd realised he had the phosphorus stick out too long and spent too long trying to scalpel a slice off, it lit up and he threw it down the sink in the fume cupboard! Water and phosphorus?!? Never did find out what happened to the drainage system

I left school in the early 60's aged 15.

I've forgotten the names of most of my teachers - and much of what they tried to teach, but will NEVER forget our science teacher Mr Jacobson who was just brilliant - every demonstration / experiment ended in spectacular chaos, but only AFTER he has succeeded in getting the point across. A very talented man and a wonderful teacher.

(and yes, one of his mishaps was with phosphorous too)

 

[tazz]

A level physics. 1985. Top teacher (ex RAF engineer). Demo'd this beautifully.

he rigged up a...well a rig at the front with thousands of windings versus well, two or three about a centimetre thick (or a centimeter if you're American) with huge clamps either end. Got a monster nail out (all to prove the amps point), asked what we thought would happen etc, then clamped the nail betwixt the ...clamps and powered up. By the way ( can't put btw it just feels wrong!!!!!) this was way before H&SE gone mad but he had a huge perspex shield for the class of grunty 17 year olds and he was wearing a mask

massive bang, nail literally exploded ( as Im sure you expected). Them were the days "ay it" still remember watching the chemistry teacher whimper and panic because he'd realised he had the phosphorus stick out too long and spent too long trying to scalpel a slice off, it lit up and he threw it down the sink in the fume cupboard! Water and phosphorus?!? Never did find out what happened to the drainage system

Used to love that experiment.....vertually zero ohms...so very high current ...V/IR again....You can buy the nails in srewfix tho...!!

 

[Knobhead]

I think you will find that all chime transformers are all DC no AC

I think you will find you are WRONG!

 

[cobrauk]

@Tony As most chimes/door bells in the UK run off battery's having a mains transformer is an extra to save having battery's that would explain why my statement was correct yes ?

 

[telectrix]

most door chimes will run on a.c. or d.c. the output of a transformer is a.c. and can only be converted to d.c. by rectification, using diodes and other wizardry.

 

[tazz]

The old convetional coil type chime will work on AC or DC, modern electronic chimes have votage regs at 3v or 5v, and can take ac or dc over 5-14v. Manufactures make products fit for purpose, knowing their customers may want dc batteries or ac transformers, unless otherwise stated on the box..

 

[Geordie Spark]

most door chimes will run on a.c. or d.c. the output of a transformer is a.c. and can only be converted to d.c. by rectification, using diodes and other wizardry.

AC/DC ...... a canny band and their chanter is from my home toon !!!

 

[telectrix]

aye, they're all gobby sods up there.

 

[Silly Sausage]

AC/DC ...... a canny band and their chanter is from my home toon !!!

They used to be a good band before him.

 

[Geordie Spark]

They used to be a good band before him.

He was in a good band before he joined them too.

 

[Knobhead]

Batteries? Things moved on from the days of the Leclanche Cells that that door contact probably first used.

In all honesty would you fit a battery bell in this day and age for use in a shop?

Arkwright had the best solution a bell on a spring.

We could go for the ultra safe method

 

[Geordie Spark]

Batteries? Things moved on from the days of the Leclanche Cells that that door contact probably first used.

In all honesty would you fit a battery bell in this day and age for use in a shop?

Arkwright had the best solution a bell on a spring.

We could go for the ultra safe method

Chuck Berry - My Ding-A-Ling (1972) - YouTube

 

[trev]

They used to be a good band before him.

Still are. Maybe not as good as before but still good.

 

[Silly Sausage]

Still are. Maybe not as good as before but still good.

No No... just about every track off the Bon Scott albums is brilliant, apart from Back in Black, you can count the decent tracks since on the fingers of one hand.
Scott's lyrics are like Shakespeare to a Geordie Sun journalist!

 

[trev]

They're still good though, like I say not as good but.....

 

[Silly Sausage]

I think I hear what your saying, still slightly deaf from seeing them at Leeds Poly, 1978, a few away from the stack stage right.
We sat on the wall outside for an hour or so waiting for us ears to stop buzzing.

 

[ayjay]

heres a good site , can any of us older fellas rememer the old pull/bell ting, the bell system? i dare say some do
also glass leclanche cells-- anyway
28DaysLater.co.uk Urban Exploitation Forums
its a strange site, i love old buildings, these folks take pics of old abandoned places

 

[Knobhead]

heres a good site , can any of us older fellas rememer the old pull/bell ting, the bell system? i dare say some do
also glass leclanche cells-- anyway
28DaysLater.co.uk Urban Exploitation Forums
its a strange site, i love old buildings, these folks take pics of old abandoned places

I'm a member, I'm decrepit and abandoned.

There's some of my reports on there.