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

Outdoor Light Controller Circuit
Touch Switch Circuit with explnation
Infrared beam barrier proximity sensor
100W inverter 12V to 220VAC
Power Supply Schematic
Simple Delay Timer Circuit
Joulethief SEC exciter and variants 64
Variable DC Power Supply Circuit
USB Host and Device
Hammond T-100/T-200/T-500 MIDIvice
A flat tire warning circuit
Using LED lights do motor phase failure protection



Top