1Hz from 60 hz main

Thread Starter

arthur92710

Joined Jun 25, 2007
307
I have a circuit that takes 60Hz from the mains and transforms it into 1hz. Can someone look at it and verify that it outputs 1 hz. Im not sure of the second counter. Thanks

 

SgtWookie

Joined Jul 17, 2007
22,230
I rather like Ron H's suggestion better. There are other options than to use two 4017 IC's.

The schematic you originally posted could be quite brutal on the Schmitt-input U1, as there are no provisions to protect it from voltage swings above/below Vdd/Vss.
 

thingmaker3

Joined May 16, 2005
5,083
Just in case anyone actually wants to us the original schematic, it should be noted that the bridge rectifier o/p is 120Hz, not 60Hz. The o/p is therefore 2Hz.
 

Ron H

Joined Apr 14, 2005
7,063
Just in case anyone actually wants to us the original schematic, it should be noted that the bridge rectifier o/p is 120Hz, not 60Hz. The o/p is therefore 2Hz.
Actually, the way the bridge is connected, it may be just a smoke generator, as it shorts out the transformer on alternate half cycles of power.
If the bridge connection is corrected, the Schmitt may be destroyed, as SgtWookie pointed out.
The 7805 is powered off the output of the Schmitt.:eek:
If the 7805 input is moved to the bridge output, then the Schmitt won't switch.
100nF is way too small for the rectifier filter.
I didn't check the logic.
 

thingmaker3

Joined May 16, 2005
5,083
Ah, yes! The old rotated bridge error. :cool: I am in great debt to the makers of Eagle Light for having the foresight to add "~" and "+" and "-" to bridge rectifier symbols!
 

Thread Starter

arthur92710

Joined Jun 25, 2007
307
Just in case anyone actually wants to us the original schematic, it should be noted that the bridge rectifier o/p is 120Hz, not 60Hz. The o/p is therefore 2Hz.
what do you mean by 120hz? It is 120v and 60 hz so what do you mean?

Oh! the bridge makes the 60hz into 120hz because the wave goes form ac to dc
like in the pic
 

mik3

Joined Feb 4, 2008
4,843
Actually this circuit does not work!! The bridge rectifier is connected in a wrong way. Also, the input of the 7805 is connected after the schmitt trigger!!!!!
 
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