I am new to electronics and I wanted to make a LED dimmer. I have connected 2 LED and a 100 ohm resistor in series. I have connected 24 of those [2 LED and resistor] in parallel to the output pin of the 555 timer. The total LED configuration only draws about 100mA so I thought of driving those LED directly using 555 timer. Here is the circuit diagram.
I plan to drive the LED configuration using 4 1.5V AA batteries in series making total of 6V. As I did that, the LED configuration drew only about 0.25 mA of current, at the voltage of 4.33V. The LED configuration was very dim due to this reason. (please ignore the cheap equipment and the mess)
The above picture shows the Output pin voltage of 555 timer. It is 4.33 V and the current is 0.25 mA shown in below picture.
I tried to power the same LED configuration by using a 12V 18A power supply. The voltage on the 555 timer output pin was around 3.8V and the current draw by the total configuration was around 73mA. The LED glowed very bright.
Above picture shows the Voltage of output pin of 555 timer and the below picture shows the current draw by the total LED configuration when powered by 12V 18A Power supply.
I don't understand why there is different current draw by the same LED configuration even though the voltage of the 12V power supply is lowered by 555 timer. What would be a good way to dim my LED configuration using 555 timer and 4 1.5V AA batteries? Is it necessary to use MOSFET to dim this configuration? please enlighten me! Thank you for your time!