I am trying to build a simple LED blinker as a nightlight for my son's bedroom, based on this circuit.
But my knowledge of electronics is basic at best. This circuit has a 10k pot that was supposed to control the blinking speed, but for some reason I don't understand it has to go to 0 to start the blinking. After that, I can turn it to the maximum value to get the slow steady fading I wanted.
But I don't want to have to turn a potentiometer manually every time the circuit starts. I'm sure there's a way to make this happen automatically using a capacitor somewhere, but as I said I'm not good enough to figure that out by myself.
Edit to add: Tried changing one of the 10k resistors (I actually put a potentiometer there to try several different resistances) but didn't work. I also tried changing one of the capacitors by a 33uF one, and then a 470uF one. The circuit simply doesn't start if I don't turn VR1 to 0.
Edit 2: I didn't have access to the CS9013 transistors, so I used a S9014 instead( the datasheets seemed similar enough for me) Also, for testing purposes I'm using a 9V power source instead of a battery.
Best Answer
You can use a capacitor in parallel with the pot (literally around the two leads) to maximize initial current flow. This should retard the timing just enough to unbalance the circuit at the start. The capacitor acts as a short when first turned on, which simulates the pot being set to zero. After some time the capacitor will charge and hold the voltage at the level of the pot.
Bonus: if you have access to a 555 timer, you can implement a more reliable blinking circuit. https://www.instructables.com/id/Flashing-LED-using-555-Timer/