I recently became interested in electronics which has been a fair mix of triumphs and frustrations... I'm a complete novice in this area.
My current project is to build a sequencing light circuit for use in a scale model kit. Due to space constraints inside the model kit, I'll be using a 6V DC power supply.
I've managed to build several working "sequencing LED" circuits on my bread board in various configurations, but none that perform as I expect. What I want is for each LED to remain lit once triggered until the entire sequence is complete.
The only example of a schematic that I could find on the web is this:
http://scdiagramwiring.blogspot.com/2013/03/sequential-led-bar-graph-circuit-using.html
While waiting for parts to arrive, I D/L the Proteus 8 Demo software (which is pretty cool stuff) and played with that, but could not get the above referenced diagram to function until I took out some resistors and tweaked other resistor/capacitor values. So I'm not sure if that schematic is functional.
When my components all showed up however, I couldn't repeat the working software behavior with the actual hardware.
I was able to build the AMV successfully on one bread board. I used a version that included LED's so that I could monitor the "flip-flop" rate and ended up using 91K resistors with 4.7u capacitors for the desired pulse rate to send to the 4017 clock pin.
While trying to build the remainder of the circuit on a separate board though, I have only been able to attain blinking LED's....
The data sheets I've read on the BT169D SCR's are conflicting information to me so I'm not sure if my 6V power supply is adequate to trigger the gates.
I've also tried removing the PNP transistor from the power flow completely to test if I could get a solid bar of lights for at least one sequence but that did not work either.... so again, I suspect the SCR's are not latching.
The last piece of info that might be note worthy is that I have determined 150 ohm resisters were ample to protect my LED's so I am not using the 1K resistors as in the example schematic above.
OK..... long winded enough? I hope this is not too much info, but still enough for any who wishes to suggest a fix.
Thank You,
Wolf
My current project is to build a sequencing light circuit for use in a scale model kit. Due to space constraints inside the model kit, I'll be using a 6V DC power supply.
I've managed to build several working "sequencing LED" circuits on my bread board in various configurations, but none that perform as I expect. What I want is for each LED to remain lit once triggered until the entire sequence is complete.
The only example of a schematic that I could find on the web is this:
http://scdiagramwiring.blogspot.com/2013/03/sequential-led-bar-graph-circuit-using.html
While waiting for parts to arrive, I D/L the Proteus 8 Demo software (which is pretty cool stuff) and played with that, but could not get the above referenced diagram to function until I took out some resistors and tweaked other resistor/capacitor values. So I'm not sure if that schematic is functional.
When my components all showed up however, I couldn't repeat the working software behavior with the actual hardware.
I was able to build the AMV successfully on one bread board. I used a version that included LED's so that I could monitor the "flip-flop" rate and ended up using 91K resistors with 4.7u capacitors for the desired pulse rate to send to the 4017 clock pin.
While trying to build the remainder of the circuit on a separate board though, I have only been able to attain blinking LED's....
The data sheets I've read on the BT169D SCR's are conflicting information to me so I'm not sure if my 6V power supply is adequate to trigger the gates.
I've also tried removing the PNP transistor from the power flow completely to test if I could get a solid bar of lights for at least one sequence but that did not work either.... so again, I suspect the SCR's are not latching.
The last piece of info that might be note worthy is that I have determined 150 ohm resisters were ample to protect my LED's so I am not using the 1K resistors as in the example schematic above.
OK..... long winded enough? I hope this is not too much info, but still enough for any who wishes to suggest a fix.
Thank You,
Wolf
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