so i am guessing that the cap is charged and holds long enough to keep relay energised.
is that correct ? if so, sounds good, i'd have to try it. on the bench 1st
stumped on a 555/556 project.
Re: stumped on a 555/556 project.
That's correct. The resistance of the coil along with the drop out voltage of the relay will determine the value of the cap needed.so i am guessing that the cap is charged and holds long enough to keep relay energised.
is that correct
Steve G.
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Re: stumped on a 555/556 project.
gotchya ok,, might also be bennificial to use a ac relay, due to the fact that they have that piece of copper on the coil to help ac relays avoid the chatter .
i'll be playing with it and keep you all updated.
i'll be playing with it and keep you all updated.
Re: stumped on a 555/556 project.
I don't think you will have any luck with an AC relay, the coil resistance is too low and they're designed for 60Hz operation. If you don't have a suitable relay you can try this transistor version. Just make sure the transistors used (either discrete or a darlington) will handle the relay coil current. With the component values shown the 50ma relay I used would hold for over 1 second.
Steve G.
Steve G.
Re: stumped on a 555/556 project.
Wouldn't it be possible to use a transistor switch in line with the power supply for the 555, driven by the
power of the turnsignal being connected to the load? I would think that would be easier/more space saving
than using a relay as suggested.
Just my take on it.
CeaSaR
power of the turnsignal being connected to the load? I would think that would be easier/more space saving
than using a relay as suggested.
Just my take on it.
CeaSaR
Hey, what do I know?
Re: stumped on a 555/556 project.
CeaSaR wrote:
Steve G.
You sure could. I prefer the reed relay option because it will give you a definative ON-OFF response. The relay listed fits in a standard 14 pin dip socket which is fairly small and using just the relay and cap would have less parts obviousy. It's dacflyer's project so I guess he will want to use what ever he already has on hand.Wouldn't it be possible to use a transistor switch in line with the power supply for the 555
Steve G.
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Re: stumped on a 555/556 project.
i just happen to have a card of them reed type relays off of a computer card for some sort of test equipment.. i'll use one of them, thanks guys..
- dacflyer
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Re: stumped on a 555/556 project.
hey all, i finally had time to finish this project, using the cap across the relay to hold a charge works great, 330uF cap worked great, hold relay for almost 1 sec after power is gone.
and i am using the ding dong chime from radio shack, that is pleasant sounding.
later i might adjust the timing cap on the 555 circuit, to give it just a little more delay before it triggers the chime..2-4 sec more..
but other than that it works great
thanks again....
and i am using the ding dong chime from radio shack, that is pleasant sounding.
later i might adjust the timing cap on the 555 circuit, to give it just a little more delay before it triggers the chime..2-4 sec more..
but other than that it works great
thanks again....
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