Question

VledD VrefD rN Dx ? UIA ?? 01 2N3904 NJM4560 GND 0r GND

to create a circuit which drives a controlled current through an LED with an
input voltage, Vref.The design performed here is a low power circuit (at most 15 mA
ows through the LED) which will be scaled up to a high powered version (300 mA) for your major project.

The voltage drop across the resistor should be large enough for the feedback voltage to not
be signicantly e ected by noise.
The resistance should be large enough for parasitic resistance in a breadboard prototype
to be insignicant. You may need to pick a value and see how accurate the nal prototype
is then adjust as appropriate.

With your chosen value for R3 designR3 must not exceed 250 mW the input voltage divider (R1 and R2 R1 + R2, must be at least 5 k) so that a value of Vref = 10 V results in 15 mA flowing through the LED. You are restricted to E12 series
resistance values, an LED current tolerance of -10%, +5% is allowed.

Answer 1

ttver LLED 2 2 eitL 2i2 z 15V -t

カISMA -Man -tu. Power , dleerd rfo-m load.. R1, .ใ Tuen 415 10K 4