Hi all, im new to forums and was wondering...

wanted to know your comments on wheather this would work..
and also ive been told to find out what the 0.10M stands for ( 10-100k )
any other usefull comments would be much appreciated

 

Hi,

wanted to know your comments on wheather this would work..

Well, if you change the transistor to an NPN and if the output device is a self contained buzzer, it'll work.

and also ive been told to find out what the 0.10M stands for ( 10-100k )

0.1 MegaOhm = 0.1 millions Ohm = 100 kOhm = 100,000 Ohm.

any other usefull comments would be much appreciated

If you don't need to boil another egg right after the first one, 2 of the diodes are a waste and the diode on the buzzer is a waste no matter.

 

thanks for that alot of help, but im actualy making a steak timer. 3 buttons ( meaning 3 of those circuits ) each button will start a timer for a different rarity of steak.

 

Hi,

thanks for that alot of help, but im actualy making a steak timer. 3 buttons ( meaning 3 of those circuits ) each button will start a timer for a different rarity of steak.

No point in 3 separate and almost identical circuits.
You could use a 3-position switch to select the time used when the button is pressed.
I could draw you a schematic. What are the times approximately ?

 

yes please , times are ....
3mins - Rare steak
4mins - Medium rare
6mins - well done
and yes i did cook steak to test these thanks for this.

 

found a decent switch.. think a 4 way rotary switch would be good enough to use?

 

Hi,

found a decent switch.. think a 4 way rotary switch would be good enough to use?

Absolutely and then you could add: 15 minutes = "incinerated"

Don't mind the odd look of the rotary switch, a single deck will do fine, but this was the only one I had in my CAD libraries and so it looks more tidy than if all the wires were crammed to a single deck.

When power is applied (put a switch in the +9V line), it will use the time allready selected by SW1.

You MUST use a CMOS version of the 555 - like ICM7555 or LMC555 - or it won't work with such long times.