Thyristors not latching?

Thread Starter

ImWolf

Joined May 26, 2013
108
Hey Ron,

I looked up those individual inverters and I could only find surface mount components....... 5 pin each...... so I guess your design isn't such a waste of space after all.

BTW: your modification on the 3909 output (which is really only clocking from pin 2 instead of pin 8) has been running for 6 hours now!

I'll be paying a lot closer attention to you from now on!

Wolf
 

Thread Starter

ImWolf

Joined May 26, 2013
108
Update:

Just so you know Ron..... you're suggested modification on the 3909 output (which amounted to simply using pin 2 instead of pin 8) ran for between 7 and 8 hours..... I wasn't there when it crapped out.

I'd call that around a 400% increase in battery life..... how did you know?

Wolf
 

Ron H

Joined Apr 14, 2005
7,063
Update:

Just so you know Ron..... you're suggested modification on the 3909 output (which amounted to simply using pin 2 instead of pin 8) ran for between 7 and 8 hours..... I wasn't there when it crapped out.

I'd call that around a 400% increase in battery life..... how did you know?

Wolf
I also recommended removing the jumper between 1 and 8. In fact, I said that, if you did not remove that jumper, then pin 8 would have better logic levels. Reread post #82.
I see no reason for increased battery life if all you did was take the output pin 2 instead of pin 8, without removing the jumper between 1 and 8.
 

Thread Starter

ImWolf

Joined May 26, 2013
108
What I said was, Pin 2 IS a good output with the new circuit I posted.
Now I'm confused Ron.... I don't see any kind of IC clocking the 74164 in your new circuit.

I don't understand how your C1/R2/U2b combo function as a clock but the Proteus simulation software likes it.

I'm liking it too.... much simpler than an AMV with 8 separate parts or even an 8DIP with it's 2 extra components.
 

Ron H

Joined Apr 14, 2005
7,063
Now I'm confused Ron.... I don't see any kind of IC clocking the 74164 in your new circuit.

I don't understand how your C1/R2/U2b combo function as a clock but the Proteus simulation software likes it.

I'm liking it too.... much simpler than an AMV with 8 separate parts or even an 8DIP with it's 2 extra components.
The clock oscillator is outlined in red in the attachment.
See this video tutorial for an explanation of how it works.
 

Attachments

Thread Starter

ImWolf

Joined May 26, 2013
108
Thanks Ron.... I was able to recognize that the three components you recently framed in a red box were somehow clocking the chip, and after watching the video I can almost understand it.... with one exception that the film maker did not explain.

When current flows through a circuit (or any device) does the current always move in "waves" of highs/lows?

I'm attaching a schematic of what I have on the breadboard now, which is pretty much exactly what Allen posted many moons ago. Except I'm still playing with that 3909 you love so much.... :b

It's actually a neat little package with a small PCB foot print... the only issue I have with it is the low battery life. (When I tried removing either the 1-8 jumper, or the 6-8 LED it quit clocking the 74164 and just gave me solid LED's).
 

Attachments

Ron H

Joined Apr 14, 2005
7,063
I could be explaining electronics to you, one question at a time, for eternity. You don't know enough for me to explain, in this forum, how the waveforms in the oscillator are generated. If you really want to learn about electronics, start with the AAC e-book, and ask questions, as they arise, in a new thread.

Your low battery life is a result of using wimpy batteries. You either have to use bigger batteries, fewer LEDs on at a time, or less current in the LEDs. As you have been told, the big current gobblers are the LEDs. The other parts are pretty much insignificant contributors to the overall current consumption.
 

Thread Starter

ImWolf

Joined May 26, 2013
108
Hey guys....

Started building the 74164-3909 circuit and then my LMC555CN chips showed up, so I decided to change out that 3909. (per popular demand). Now I'm having difficulties with the 555.

Having already chopped my blank PCB down as small as possible to suit the previous design, I went hunting for the smallest 555 oscillator package I could find and came across this:

http://www.555-timer-circuits.com/simplest-555-oscillator.html

When I tested it in Proteus it ran fine, but I can't get it working on the breadboard. I'm using a variable power supply set at 6V, and I've tried different combinations at R21 and C2.

So, for now.... can anyone please comment on;

1) Is the above linked oscillator viable/appropriate to use with this circuit?

2) Did I make a correct representation of it in Proteus? (below)

Thanks,
Wolf
 

Attachments

Thread Starter

ImWolf

Joined May 26, 2013
108
I breadboarded the 74164 circuit and found that it was working fine. Instead of using the astable multi-vibrator circuit I am using a 555. If you're using 6V for Vcc it might be too high and can spoil the 74HC164 in long run. Just put a 1n4001 or 1n4148 in series with the 6V battery on the positive terminal before entering your circuit.

I'll post my breadboard when my photo is ready.

Allen
Just tried adding the extra resistor and changing jumpers around to match the configuration of Allen's schematic (post #44 back on Pg. 5). Same results though... with each instance of power on I have a random number and series of solid LED's.

I thought this would be a simple swap?
 

Thread Starter

ImWolf

Joined May 26, 2013
108
Looked back and found an obvious problem at 555 pin 5.... once I wired it properly through the 0.1u capacitor and then to ground I did get some sort of "oscillation".... but nothing that appears sequential or repeating.

All 8 LED's seem to flash twice quickly, then once after a short delay... and they are not doing this in unison.

Pretty weird.

:b
 

Ron H

Joined Apr 14, 2005
7,063
I have circled a couple of corrections. The clock input voltage to the 164 cannot be allowed to exceed its rail voltages. You guarantee this by running the 164 and the 555 on the same supply voltage.
The NPN's base current only needs to be ≈Ic/10. The 1k in your schematic unnecessarily loads the 164 output, which will cause LED8 to be slightly dimmer than LED7. Change the base resistor to 100k.
 

Attachments

Thread Starter

ImWolf

Joined May 26, 2013
108
Thanks for pointing out that clock V input issue Ron..... that one mistake probably cost me most of the troubleshooting time. I hadn't noticed a diminished LED8, but changed that R out too.

The reason I had configured the two diodes as I had was because with the previous circuit using the 3909, I had to tone the V to the 74164 down closer to 4.5V for some reason. But I've just found that when I went with the 555 instead, I don't need the diodes at all.

In other words, with a 555 rated at 5V minimum, and a 74164 happiest at around 4.5V (or so I thought), it seemed like the best way to go.

I wish I could find a 6V battery supply that wasn't so flaky and weak. This has probably been the Achilles heel in everything I done recently. It would need to be a package smaller than a standard 9V battery though for fit.

After success with the variable power supply I went back to the battery pack and that worked fine.

No one commented on that "simplest 555 oscillator", but I also switched back to that configuration and it behaves identically.

So, I do have that bit of good news, since (along with 2 diodes) I was able to eliminate 3 components from the circuit.

Anyway... thanks for taking the time to post that clock issue Ron. My 74HC14 showed up recently so after I complete this board I'll build your circuit next.

Wolf
 

Ron H

Joined Apr 14, 2005
7,063
What brand of battery are you using? I saw one technical paper that reported on a test of several brands, including a couple of "no-name" ones. The no-names only had about 50% of rated capacity. Sonys were the best. If you haven't tried them, I would recommend you do so.
There are slightly larger lithium coin cells available, with somewhat higher AH specs, but they appear to be pretty pricey, and I would be very leery of "no-names".
 

Thread Starter

ImWolf

Joined May 26, 2013
108
I've been using two different "no name" brands of CR2032 that came with some switching holders I bought..... Suyu, and Eunicell.

I did look up the spec's on them, and they seemed pretty much the same as far as mAh goes.... but I've had better luck with the later all the way around.

Next time I'm out and about I'll pick up some Sony and experiment.

Thanks,
Wolf
 

Ron H

Joined Apr 14, 2005
7,063
Finished a second version of this project...... thanks for all the help guys!

http://www.youtube.com/watch?v=Ib9JNm3pEzk&feature=youtu.be
Nice video!
FWIW, schematics are ONLY intended to show electrical connectivity. They are almost never arranged to show physical features or topology. They make perfect sense to an EE or electronics technician.
I personally strive to make schematics easy to read (for an engineer or a tech). Back in the '70s, we drew schematics by hand, they were redrawn by draftsmen, and PC boards were laid out with tape on mylar (no computers). I worked with an engineer who would cram as much circuitry on a C (17" x 22") sheet of paper, or D (22" x 34"), or sometimes even E, as he could. They were a nightmare to read and follow signal paths. I remember one where he had to add a connection from one corner of the paper to the opposite corner, after the sheet was already crammed with circuitry. It looked like the path you would draw when tracing a maze.
Somehow, the drafters were able to turn these into neat, readable schematics, and the layout guys understood that schematics were not topological representations of the circuits.

BTW, you could shrink your boards to less than half size if you switched to surface mount devices. You would have to have excellent soldering skills, though.
 

Thread Starter

ImWolf

Joined May 26, 2013
108
Glad you liked the video Ron...... Thanks... :b

Most of your other comments brought back memories..... I had taken an electro-mechanical drafting class in high school (circa 1977), and spent most of the second year pin striping Mylar with that red and blue tape!

I gave up aspirations of a drafting career after that class! (quite boring).

Alec_T over at ETO also suggested surface mount boards as a way to shrink the final size down, but my soldering skills are barely adequate to work with the .100 hole spacing I've been dealing with thus far..... perhaps after I use up my current stock of goodies, I'll be able to give that a try.

Q: is there something non-conductive I can use to coat the back side of my circuit boards to protect any solders that might fail down the road? Is there a standard procedure like this?

Thanks....
Wolf
 

Ron H

Joined Apr 14, 2005
7,063
Glad you liked the video Ron...... Thanks... :b

Most of your other comments brought back memories..... I had taken an electro-mechanical drafting class in high school (circa 1977), and spent most of the second year pin striping Mylar with that red and blue tape!

I gave up aspirations of a drafting career after that class! (quite boring).

Alec_T over at ETO also suggested surface mount boards as a way to shrink the final size down, but my soldering skills are barely adequate to work with the .100 hole spacing I've been dealing with thus far..... perhaps after I use up my current stock of goodies, I'll be able to give that a try.

Q: is there something non-conductive I can use to coat the back side of my circuit boards to protect any solders that might fail down the road? Is there a standard procedure like this?

Thanks....
Wolf
Conformal coating is generally used to protect a board from moisture. I don't think it will provide much protection from solder joint failure due to poor soldering. I could be wrong. I was wrong once before.:D
 

Thread Starter

ImWolf

Joined May 26, 2013
108
Hey Ron,

Regarding the circuit you attached to post #85, I need to pester you just a bit..... :b

1) Ugly as it may be, is my attached schematic an accurate representation of your design?

2) Do the inputs (my pins 5, 9, 11, and 13) of 74HC14 need to be grounded in the hardware version?

3) How would I modify the circuit so that the LED's sequentially latch ON only, and then all shut off before repeating the cycle?

4) At the risk of offending you..... did you forget some resistors along the way? If I restrict current to the serial inputs of 74164. or the reset, or any place else, will that save me any battery life?

Thanks....
Wolf
 

Attachments

Ron H

Joined Apr 14, 2005
7,063
Hey Ron,

Regarding the circuit you attached to post #85, I need to pester you just a bit..... :b

1) Ugly as it may be, is my attached schematic an accurate representation of your design?

2) Do the inputs (my pins 5, 9, 11, and 13) of 74HC14 need to be grounded in the hardware version?

3) How would I modify the circuit so that the LED's sequentially latch ON only, and then all shut off before repeating the cycle?

4) At the risk of offending you..... did you forget some resistors along the way? If I restrict current to the serial inputs of 74164. or the reset, or any place else, will that save me any battery life?

Thanks....
Wolf
1) Looks good.
2) Yes.
3) I'll think about this when I have more time.
4) No additional resistors are needed, nor will they save battery life.
 
Top