Circuit drives and quantities LEDs


Posted on Jul 27, 2012

The circuit mixes LEDs of different forward-bias requirements, yet keeps the loads reasonably well-balanced through use of a current mirror comprising transistors Q1 through Q4. It also eliminates the need for a separate current-limiting `ballast` resistor on each LED or string of LEDs and provides a common control point (IC1`s ADJ pin) for adjusting the LED intensities. Transistors Q2 through Q4 mirror the current in the diode-connected transistor, Q1. Note that the Q1 current-set string (LEDs D3 through D5) should have an equal or larger voltage than that of subsequent LED strings.






Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

Bass Tuning circuit
Guitar fuzz
Sequential timer
Operational-amplifiers
Digital-logic-probe
Multimeter Shunt
Adjustable 20V Supply Circuit
audio sine wave generator
BU8732AKV Codec Ic For Digital Mobile Phone
mosfet voltage regulator
External wiring diagram of PLC



Top