RGB LED as Status Indicator
Here's the plan:
2 independent channels in a single box (an overdrive and a booster) with 1 slot for 5mm RGB (common anode) LED for status indicator.
So I came up with a switching circuit that performs the following:
1) If the booster is on while the OD is bypassed, red color will light up.
2) If the OD is on while the booster is bypassed, green color will light up. &
3) If both are on, blue color will light up.
The thing is, I tried to test this circuit on a breadboard but only green and red colors are working fine. But when I test the blue part out of the circuit with a simple battery and resistor, it is still working.
Questions are:
1) Could I have missed something in the circuit? I assume logic diagram is 99.9% correct.
2) Could I power the inverter and AND gates more than +5VDC?
Thanks in advance.
Nicko
2 independent channels in a single box (an overdrive and a booster) with 1 slot for 5mm RGB (common anode) LED for status indicator.
So I came up with a switching circuit that performs the following:
1) If the booster is on while the OD is bypassed, red color will light up.
2) If the OD is on while the booster is bypassed, green color will light up. &
3) If both are on, blue color will light up.
The thing is, I tried to test this circuit on a breadboard but only green and red colors are working fine. But when I test the blue part out of the circuit with a simple battery and resistor, it is still working.
Questions are:
1) Could I have missed something in the circuit? I assume logic diagram is 99.9% correct.
2) Could I power the inverter and AND gates more than +5VDC?
Thanks in advance.
Nicko
- mictester
- Old Solderhand
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Your logic looks OK. however, you can't power the 74LS ICs with more than 5 Volts or they will get very hot and die! What series resistor values are you using for current limiting / dropping to the LED elements? You may not have enough current available for the blue part of the LED.
I prefer to use CMOS - it's much less current hungry, and works OK on any voltage from 3V to 18V, though for the kind of circuit you're proposing, I'd use four transistors, some diodes and some resistors!
I prefer to use CMOS - it's much less current hungry, and works OK on any voltage from 3V to 18V, though for the kind of circuit you're proposing, I'd use four transistors, some diodes and some resistors!
"Why is it humming?" "Because it doesn't know the words!"
- mictester
- Old Solderhand
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You're right except that you'd need current limiting / dropper resistors for each section of the LED. The reason that I'd use logic is that I'd use momentary switches and CMOS analogue switches (4066 or 4053) and could do all sorts of clever switching schemes with little effort.KMG wrote:In my opinion it is simpler generally without the logic
"Why is it humming?" "Because it doesn't know the words!"
- lolbou
- Old Solderhand
Even if one part of the LED is used at one time?mictester wrote:You're right except that you'd need current limiting / dropper resistors for each section of the LED.
- Are you a mod or a rocker?
- Uh, no, I'm a mocker.
- Uh, no, I'm a mocker.
- mictester
- Old Solderhand
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Yes - the red part will need the least current, the green a bit more and the blue most of all. The voltage drop across the segments will vary too.lolbou wrote:Even if one part of the LED is used at one time?mictester wrote:You're right except that you'd need current limiting / dropper resistors for each section of the LED.
Incidentally, I used to use a bi-directional Red / Green LED (actually two LEDs in the same package wired in opposite directions) for asymmetrical clipping in my pseudo-Tubescreamer pedals, because of the difference in the voltage at which the sections went into conduction.
"Why is it humming?" "Because it doesn't know the words!"
- lolbou
- Old Solderhand
Oh ok... I would have expected the different colors requirements to be matched since these are in the same package. I've never used bicolor LEDs for anything, but as I suggested in your thread, I've thought once about using them for clippers.mictester wrote:Yes - the red part will need the least current, the green a bit more and the blue most of all. The voltage drop across the segments will vary too.
Obviously I would have expect a symmetrical clipping ...
- Are you a mod or a rocker?
- Uh, no, I'm a mocker.
- Uh, no, I'm a mocker.
- KMG
- Solder Soldier
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What can you say about this schematic But if you use non latching momentary switches you need to use triggers to hold state after switch is released.mictester wrote:You're right except that you'd need current limiting / dropper resistors for each section of the LED. The reason that I'd use logic is that I'd use momentary switches and CMOS analogue switches (4066 or 4053) and could do all sorts of clever switching schemes with little effort.
- KMG
- Solder Soldier
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- KMG
- Solder Soldier