Basically I want to create a blinking unit to drive my LED's. The LED's are used to be driven at a frequency of ~1.5Hz (that made me choose the values of L and C).
So here is my schematic. (I am physicist so there might be some issues with current direction…)
(The PNP is used to block the supply-current if the capacitor is charged.)
simulate this circuit – Schematic created using CircuitLab
After a while of thinking about it I got to the point that this wont work because the resistance in the LC-circuit will cause that there wont be any oscillation. Even if in D3 is only a single LED…
And now I have no idea how to get my 12V DC current into a 12V AC current with a frequency of 1.5Hz. I searched a long time how to do this but I don't get it how to get it working.
I found i.e. circuits of power inverters but all of them (I found) are at 50Hz and 230V AC output.
How could I get it working to transform my 12V DC to 12V AC (f=1.5Hz) without using an IC. Well I thought of using a quartz but no one I found has a sufficient low frequency…
Best Answer
Get a 555 timer chip. No programming necessary and there are a gazillion circuit ideas on the net. Google "astable oscillator". It should be able to directly drive a LED directly but if you need more power use a mosfet amplifier.
EDIT to show a calculator for the 555
This website has calculators for various 555 timer circuits. Here's a picture: -
Note the values of R1, R2 and C - these give a frequency of basically 1.5Hz and a duty cycle of about 51%. This is how easy it is but take note that power supply voltage variations will "tweak" the results slightly.
Here's another one: -