Hello
This is not a basic question about why a base resistor is required for a transistor. -_-
I am switching a LED with a constant current circuit. The LED must have a minimum of 5mA triggering current, but should be immune to supply variations. As such, I designed a basic constant current driver using a 2N2222A transistor (MMBT2222). The appeal is that a single resistor and transistor is required.
The supply line ranges from 10-24V. The transistor is switched using a 5V microcontroller pin.
This circuit simulated fine and works well. However, in my research I found an untraceable picture of a similar circuit, with a fundamental difference of a base diode.
My question is why is this circuit recommended? I wish to avoid adding any circuitry more than is required.
Thank you
This is not a basic question about why a base resistor is required for a transistor. -_-
I am switching a LED with a constant current circuit. The LED must have a minimum of 5mA triggering current, but should be immune to supply variations. As such, I designed a basic constant current driver using a 2N2222A transistor (MMBT2222). The appeal is that a single resistor and transistor is required.
The supply line ranges from 10-24V. The transistor is switched using a 5V microcontroller pin.
This circuit simulated fine and works well. However, in my research I found an untraceable picture of a similar circuit, with a fundamental difference of a base diode.
My question is why is this circuit recommended? I wish to avoid adding any circuitry more than is required.
Thank you