RE: help needed with simple circuits

["Keith Doxey" <ukha@xxxxxxx>]

a  Main ON/OFF switch

b  Limit the current through the LED

c  So the buzzer is silent at night

 

d Cant draw so ....

 

    Replace switch 2 with LDR.

    LDR has low resistance when light shines on it so buzzer would operate

    LDR has very high resistance when dark so buzzer does not sound.

 

did I pass ?

 

Didnt do electronics at school.....the stuff they did in the CSE coursework I had done whan I was 6 or 7 :-))

 

Being a school in a Rural area they did lots of farming/biology stuff. Have to say I dont like cutting up Worms/Frogs etc and on more than one occasion came very close to spilling my lunch on the benches in the science lab :-((

 

Keith  aka the squeamish one !!

 

PS. I turned the paper over as oper the instruction at the bottom but the other side was blank, does this mean

 

a There was only one side of information

b I only have a single sided printer

c I'm stupid

d All of the above

 

:-)

 

 

 

 -----Original Message-----
From: Timothy Morris [mailto:timothy.morris@xxxxxxx]
Sent: 02 June 2001 17:35
To: ukha_d@xxxxxxxSubject: [ukha_d] help needed with simple circuits

I help a small group of 13 year old boys with their common entrance science revision.

 

Apologies for sending an attachment to the list, but can someone answer these questions. I think I've got it right but I want to check, as they have their Physics exam on Tuesday.

 

Tim.

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