JFETs make a simple and cost-effective constant-current source. Paul Rako breaks down why you should consider these tried-and-true devices.

This is a very simple led constant current design using only 2 transistors, 2 resistors and an LED. This circuit allows you to use any voltage between 2V ...

By using dual bipolar devices in one case, the manufacturer nearly perfectly matches the two devices. Although this Design Idea describes a positive power supply, you can realize a similar ...

But from there he moves on to the juicy bits. He builds a transistor-based constant current driver, then adds voltage regulation for the circuit as seen in the schematic on the left.

Over on his YouTube channel [Aaron Danner] explains biasing transistors with current sources in the 29th video of his Transistors Series. In this video, he shows how to replace a bias resistor (and… ...

Download this article in PDF format. High-brightness visible-light LEDs (VLEDs) require a constant-current source. This simple, RFI-free circuit takes advantage of the normally-on properties of ...

The voltage source varies between 0V and 20V, and there are three constant current circuits (from the left): The normal constant current circuit, one with the same transistor in the reversed-collector ...

The two-transistor circuit gives the pale blue trace, which seems reasonably well behaved aside from some small wibbles. To look at the constant current circuits with different pwm voltages at 10kHz ...

Now researchers have developed a new type of transistor that is 50 times more energy efficient than today's models. It is also the first to be developed using nanotechnology.