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Oh like a DC/DC stepdown converter? That seems both costly and are way too large fit anywhere in my setup..
Actually im trying to make this wordclock:
And i have programmed my ATmega16 to switch the 24 outputs for LEDs
The VCC on µC is 5V, and i just had a 12V DC supply at hand so i thought...
What is the advantage from Rdson FET compared to darlingtons?
The reason i chose those, were i had access to an IC array, so i could easy place 3 of these instead of 20 singles..
You mean regulate the current with a voltage regulator like: LM317 ?
Thank you
Sure, this would illustrate my circuit, though i have 20 outputs to control transistors, and in some of the transistors there are 2 LEDs..
DC forward current = 30mA
Hello all!
I have a circuit with 20 White LEDs, which change with time controlled from a µC and transistors, 3 to 6 of these are ON at the same time
From the LED-datasheet i read:
"Forward Voltage 3.3V"
My circuit supply is 12V, so normally i would serie connect the LED with a resistor to make...
Oh, in the test schematic i just put in some components to show how its wired, im not sure the current is 424µA (this was measured when a 10kOHM resister was in R2s place)
So i guess the best is to just go with the 2,7kOHM resistor, when i dont know this current?
Thanks to both of you for your...
Hello everyone
I have a circuit where my µC (ATmega16) triggers a transistor (ULN2001) to open for a LED
I know i need a resistor between the ATmega16 output and transistor base to limit the current, but i cant figure out which resistor value would be best?
I guess too low would waste power...
Well 4017 dosnt have a state where all are low.. But just dont connect anything to Q0, and connect your arrays to Q1 to Q9, then when Q0 is active, all your LEDs would be low..
Oh yea, 7805 seem like a much better solution!
And yea im not 100% sure what LEDs/battery to use, so i messed up the 9 and 12V.. And if i use the 7805, would it matter if i used 9 or 12V?
What capacitors would you suggest? I found:
0,33µF and 0,1µF, does these seem reasonable...
Hi all!
Im building a small project with an µC (ATmega16), some ICs (ULN2001A) and some "12V strip LED", so i need both 12V DC for the LEDs and 5V DC for the µC..
So my thought was using a 12VDC supply and "reduce" part of this to 5VDC for the µC
Is the best and most effective way to this with...
Yea ofc
The purpose of the circuit is, sharp noises (like when you clap your hands), will make a 230V relay open or close. Then this relay can controll ie the bedroom lights..
The purpose of my problem (the timer) i can explain with a paint illutration:
The first graph shows the voltage of the...
Adjust signal (monostable 555 timer)
Hello everyone
Im building a clapswitch, and i have most of it working
The schematic is here:
My problem is after the first op amp, a clap will produce several pulses, and the counter will count all of them, so i need some way to turn these signals into...
Hello everyone
Its not really homework, but needed for a project in school
Our input signal is AC -2.5V to 2.5V from another circuit, and we need to "raise" this signal to 0-5V
(ex. so -2.5V equals 0 and 0.5V equals 3V, and so on)
Is there an easy way to do this?
We tried something with...
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