Circuit switches bipolar LED


Posted on Oct 24, 2012

The circuit in Figure 1 represents one method to switch a bipolar, two-color LED using an SPDT mechanical switch or relay. This circuit wastes power and does not work properly if the power-supply voltage is not substantially more than the sum of the LEDs` forward voltages. The circuit is, therefore, marginal, to the point of being unusable, with a 5V supply and a red or green LED, which typically has a total forward voltage of 4V. You can use a circuit resembling a flip-flop (Figure 2) that doesn`t suffer the disadvantages of the circuit in Figure 1. It adds only one VCE(SAT) voltage to the VF of each LED, so plenty of headroom exists with a 5V supply and a series resistor to control the LEDs` current.






Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

Led flasher
Successive approximation a-d converter
Gas and smoke detector
Transmitter Precision Thermocouple Amplifier Circuit
800W high power mosfet amplifier Schematic Diagram
17 colpitts ham lesson
protected
arduino scanning backlight
Pulse Generator And Signal TracerCircuit
Vacuum Fluorescent Device Regenerative Receiver



Top