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  #1  
Old 02-10-2010, 11:44 PM
aq_rules aq_rules is offline
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Default Intermittent Relay...

Hey,
These Days I was working on a home work project, its a team work,our task was to turn a simple car into a completely sensor loaded car...well our car is equipped with all the sensors which were required but now we want to place a wiper on the rear glass(windshield,i dun noe ny better word for this)....we are done with the fitting nd all other procedures but now what we want is an intermittent relay switch circuit which turns on the wiper for 2 seconds and stops for 5 seconds and repeat the cycle until the switch is turned off.....i hope u guyz getting this...

It would be better if u guys would upload some schematics....i want a simple schematic which only have the electronical components and a relay,not the wiper motor nd all those things, because i'll simply connect the loose wires which i've left under the cars steering...so i'd like to see the basic circuit diagram....

Plzz help..
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Old 02-11-2010, 12:16 AM
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You can always use a 2N2646 UJT as a relaxation oscillator that trips the relay. Jameco still carries them.
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Old 02-11-2010, 02:38 AM
aq_rules aq_rules is offline
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plzz cn u give a lil more explaination
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Old 02-11-2010, 12:34 PM
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Here is what our Ebook has to say - http://www.allaboutcircuits.com/vol_3/chpt_7/8.html

Google is pretty easy to use as well.
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Old 02-11-2010, 07:37 PM
aq_rules aq_rules is offline
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yea i noe that:P:P....found nothing there thts y m here...
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Old 02-12-2010, 02:00 AM
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Okay - put base1 to ground and place the relay coil between +12 volts and base 2. When the UJT fires, the wiper will start a cycle.
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Old 02-12-2010, 09:56 PM
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one more question....how will i set the timer?? of 2 and 5 seconds...2seconds on and 5seconds off...
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Old 02-12-2010, 11:22 PM
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A 555 would be a lot simpler. This sound like a job for...

Bill Marsden!

Bill, where are you, boy?
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Old 02-13-2010, 05:53 AM
aq_rules aq_rules is offline
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yea bill, plz help, where r u???
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Old 02-13-2010, 12:32 PM
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I just back from work (OT), when I get a chance I'll see what I can do. I've been catching up on the forum whilst eating my raisin bran.

How long do you want it to stay off as a maximum duration?

A suggestion, go through my various threads and blog, and see what comes closest to working for you. When I get back I'll help out, either tweaking your solution or suggesting something I think is better. This way you get some practice designing. It is more than half the fun I think, and if it works you get bragging rights (if it doesn't it's my fault ).
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