If I have 6 leds in paralell and want to use a pot to control their brightness then would a pot reduce them all or would it reduce the number of leds lit. It makes sense to me both ways.
To change the voltage control led brightness is not feasible
Control the duty cycle with pot
Methods: make an oscillator circuit, the output square wave for the LED,
Control the duty cycle square wave with a pot, you can control the brightness.
I been doing some more thinking. What if I used a 317 circut to regulate the voltage, I feel like that would work, but i would be force to keep the voltage above 1.2v. I am only familiar with using a 555 to create a square wave, what are some other popular methods.
I been doing some more thinking. What if I used a 317 circut to regulate the voltage, I feel like that would work, but i would be force to keep the voltage above 1.2v. I am only familiar with using a 555 to create a square wave, what are some other popular methods.
What PCBWING is getting at is that to control LED brightness or vary it you don't generally vary the voltage to your LED. Generally you would use PWM (Pulse Width Modulation). The posted circuit using a 555 timer would give you a blinking effect with the LED on and off for equal periods of time. To get an understanding of using PWM to control LED brightness give this a read. That may help clarify things.
I understand PWM but with a 555 how do you get below a 50% duty cycle. I would like the leds to go from all the way off to all the way on. I have been google, and found the hex inverter circut **broken link removed**
The problem is that I heard the the output is very irregular. I think that is a problem and there is a better way of doing it.
You don't need PWM or any complex circuit. Just a simple transistor with a pot on the base to control the base current. Put the LEDs in the collector circuit and they will change in brightness.
You don't need PWM or any complex circuit. Just a simple transistor with a pot on the base to control the base current. Put the LEDs in the collector circuit and they will change in brightness.
I didn't know that was even possible, I thought that the transistor is either on or off. Could you explain it to me alittle more, I am very interested by this. Where should I start in finding the right value.
Simply put a 1M pot between positive rail and base with a 10k stopper resistor in series and put the LEDs in the collector circuit with 470R resistor on a 12v supply.
'Quite tricky' may be over stating it. If you don't care about variation between one transistor to the next, and you don't care about linearity or temperature sensitivity is acceptable, it can be made to work.