Kitchen timer to drive a relay

lyonsie

Joined Jan 13, 2013
7
I'm going to say yes. You would need to replace the relay and change some resistor values.

Ken
Thanks i might try building this with some lower powered transistors and see how i get on. I studied electronics 20 years ago and this will be my first go back at it in about 15 years so i do have some knowledge inside somewhere, ill just have too root it back out lol. :)
 

lyonsie

Joined Jan 13, 2013
7
Cheers Ken, thanks for your help. im going to head to Mapllin now tomorrow and buy some stuff to keep me busy over the christmas hols.
 

lyonsie

Joined Jan 13, 2013
7
Cheers iv been looking online at my local store the only component i will seem to have any difficulty getting will be scr1. Would i be correct in saying this is a rectifier? and would the likes of MBR1535CT be a suitable replacement?
Also the relay is likley to be an N15AW (provided there in stock.,lol)
 

Brownout

Joined Jan 10, 2012
2,390
In your original schematic, the voltage at the SCR gate will only be a few millivolts. You need a voltage gain stage for your transistor amplifier to get the voltage to a level to fire the SCR.

Didn't realize this thread was so long. Someone might have already pointed this out.
 

lyonsie

Joined Jan 13, 2013
7
In your original schematic, the voltage at the SCR gate will only be a few millivolts. You need a voltage gain stage for your transistor amplifier to get the voltage to a level to fire the SCR.

Didn't realize this thread was so long. Someone might have already pointed this out.
Sorry this is my fault. I probably should have started a new thread instead of continuing this one. (lol im new)

The schematic i was asking about changing down to 9v is the one on post 75 and any questions i asked were based on that. Is this the schematic you were talking about? Thanks for your reply by the way. :)
 

KMoffett

Joined Dec 19, 2007
2,918
Cheers iv been looking online at my local store the only component i will seem to have any difficulty getting will be scr1. Would i be correct in saying this is a rectifier? and would the likes of MBR1535CT be a suitable replacement?
Also the relay is likley to be an N15AW (provided there in stock.,lol)
No, the SCR1 (2N5064) is a sensitive-gate silicon controlled rectifier. The MBR1535CT is a Schottky rectifier. Two totally different animals.

No, the N15AW is a 12V relay. For a 9V supply, you need a 9v or 5V relay.

Ken
 

lyonsie

Joined Jan 13, 2013
7
No, the SCR1 (2N5064) is a sensitive-gate silicon controlled rectifier. The MBR1535CT is a Schottky rectifier. Two totally different animals.

No, the N15AW is a 12V relay. For a 9V supply, you need a 9v or 5V relay.

Ken
Thanks again, yep i spotted my mistake about the rectifier in the store this morning, i couldnt get a 2N5064 all they had was a CP106D but i think that will do the job. Also got quite a selection of components (although i bet if i go to make something else ill be short something) :) Its a more expensive hobby than i had anticipated i spent over €300 lol the missus will kill me if she finds out, anyway hope to get this working over the weekend
 
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