Re: Ripple Current ?
Hi PCBONEZ, Gianni, and Folks,
Well, the circuit is working reliably through many cycles!
I want to thank all of you for your kind help!
If I didn't have you guys to bounce ideas around with, I probably would never have tried the circuit!
I have passed this circuit on to a couple other hobbyists who wanted to do the same thing.
Take care, Joe.
Joe Rampolla
Member
Last Activity: 10-04-2008, 07:23 AM
Joined: 02-23-2008
Location: Pennsylvania, USA
-
Re: Ripple Current ?
Hi Gianni,
Many thanks for the information! I found a tutorial on the internet that showed how to test a NPN transistor, and they used a 10K resistor as R2 with a 9 V power supply. When the circuit didn't work, at first I thought that I damaged the transistor when I soldered to it. I did use a heatsink (alligator clip) when I soldered. I had a 20K resistor, so that was the reason I used that value for R2.
I have been testing the circuit for many cycles now. I was watching for some heating of the transistor, but it stays cool....Leave a comment:
-
Re: Ripple Current ?
Hi Folks,
Well I tired a few other things because I felt that the resistor I eliminated might have some protective effect for the circuit. By making R1 400K ohm (with R2 at 20K), it only shaves off about 4 seconds of "on" time, as compared to it not being there at all. So the circuit is in its original design.
Take care, Joe.
...Leave a comment:
-
Re: Ripple Current ?
Hi Folks,
I made a mistake in my post above. I should have said that the 2 caps I used are in parallel, not in series. I corrected the wording in the diagram.
Take care, Joe.Last edited by Joe Rampolla; 09-29-2008, 10:10 PM.Leave a comment:
-
Re: Ripple Current ?
Hi PCBONEZ, Gianni, and Folks,
Well, I couldn't get the circuit to work with R2 at 30K, but when I reduced the resistance to 20K, it worked great. I eliminated R1 since it caused the cap to discharge too quickly. In my new diagram, R2 is now R1. I found that I get approx 45 seconds of "on" time for every 1000uF of capacitance. I used 2 1000uF 35 V caps in series.
Would all TIP31C transistors behave the same? Both the TIP31C transistors I tried wouldn't work with the 30K resistor. Is 20K enough to protect the transistor?...Last edited by Joe Rampolla; 09-29-2008, 05:15 PM.Leave a comment:
-
Re: Ripple Current ?
Hi Gianni,
Actually, that information about the relay contacts was very informative!
There are no mistakes in life, only learning experiences!!!!!!!
Take care, Joe.Leave a comment:
-
Re: Ripple Current ?
Hi PCBONEZ,
Very much appreciate all the help and info! When I get this circuit built, I will post all the results of my experimenting. I ordered some parts last night and should have it done within a couple weeks or less. The best part of this is the learning. It's great fun! Thanks for helping me understand the circuit. It really helps when I can wrap my head around it.
Take care, Joe.Last edited by Joe Rampolla; 09-23-2008, 06:54 PM.Leave a comment:
-
Re: Ripple Current ?
Hi PCBONEZ,
Thanks again for the kind help!
Is there anything that can be done when using a reed switch on an AC circuit with AC passing through the reed's contacts, to preserve them? I have one situation where I notice a brief spark within the glass tube. On a similar DC circuit, the snubber diode does the trick. Perhaps the best solution is just to convert the circuit to DC. (I use AC with the Lionel type 3 rail O gauge trains.)
Thanks!
Take care, Joe.Leave a comment:
-
Re: Ripple Current ?
Hi PCBONEZ,
Thanks for the correction! Once I redrew it according to your directions, it now makes sense to me.
Take care, Joe.Leave a comment:
-
Re: Ripple Current ?
Hi Gianni,
Thanks for the information about the relay contacts! I am learning something new all the time!
Take care, Joe.Leave a comment:
-
Re: Ripple Current ?
Hi PCBONEZ, Gianni, and Folks,
I learned the hard way about the importance of snubber diodes when I had a reed switch's contacts burn out prematurely. Would a little capacitor across the reed switch also help protect the reed's contacts? I use this circuit quite a lot, but without any cap across the reed. Am I correct in using a cap this way? Thanks!
Take care, Joe.Leave a comment:
-
Re: Ripple Current ?
Hi Gianni,
Thanks for the warning! I intend to use a switch rated 5 Amps @ 125VAC. I assume that will be heavy enough for a 12 VDC, 500 ma power supply, and an electrolytic cap 470 uF, 35V or as high as 1000 uF, 35 V.
Take care, Joe.Leave a comment:
-
Re: Ripple Current ?
Hi PCBONEZ,
Many thanks for your help and great explanation!!!!!!!!!
So I going to order some resistors and caps in values I don't already have, and give it a try. I can't find the transistor 2SC2002, but I am going to substitute a TIP31C.
Take care, Joe.Leave a comment:
-
Re: Ripple Current ?
Hi again Folks,
To simplify my question, would this work just as well?
Thanks!
Take care, Joe.Leave a comment:
-
Re: Ripple Current ?
Hi Folks,
Although this is not about ripple current, I figured that you guys know my shortcomings and have helped me here before.
I want to build this simple circuit.
This is from the site: [URL=http://www.electronics-project-design.com/TimingLight.html]http://www.electronics-project-design.com/TimingLight.html[/URL]
[COLOR=Navy]"This analog timing light project uses RC circuit as a delay OFF timer to control the duration an incandescent light turns ON. When...Leave a comment:
-
Re: Ripple Current ?
Hi Folks,
Again, thanks, everyone, for the help!
Take care, Joe.Leave a comment:
-
Re: Ripple Current ?
Hi StarFury1,
Thanks for the info!
I don't need a lot of power for most of these little projects when I use the "wall warts." Most of them have some sort of filtering, and a fuse which affords some protection. I usually use another fuse or little circuit breaker on the line, and another little diode just to help me remember the positive wire. (I like to use regular little diodes to give me some voltage reduction. My favorite low tech way to get a few volts reduction is just to use a string of diodes and allow for their...Leave a comment:
-
Re: Ripple Current ?
Hi StarFury1,
Again, thanks to you and everyone here for all the kind help!
I didn't coin the term "electronic flywheel" and I didn't invent the idea. Some clever people before me did that. Some used a small resistor to slow the discharge of the cap, others used computer grade super caps, recently. The best thing is the bipolar cap, but they, last time I checked, only go up to 16 volts for 3300 MFD. (When I use the bipolar 16 volt cap, I only give the track a fixed 7 VDC from a wall transformer that has some sort...Leave a comment:
-
Re: Ripple Current ?
Hi Folks,
Thanks, everyone, for all the great information and attention to my questions. This has been very helpful to me, but a good bit of it is beyond my knowledge, as you probably have gathered by now.
I am going to look over all the new links and see what I can do.
The model train hobby is so technical now that it might be the right combination of fun and technical stuff for all of you here on this forum. I like the hobby for stress relief! I suggest that many of you stop into a hobby shop and look at the...Leave a comment:
-
Re: Ripple Current ?
Hi PCBONEZ,
Sorry I didn't know that a PI filter is a capacitor-input filter. You hit the nail on the head a few days ago. Thanks!
Take care, Joe.Leave a comment:
No activity results to display
Leave a comment: