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His post #59 shows the common-emitter transistor driven from a 50kHz square-wave so it is dimmed a little with PWM.I thought he wanted it dimmable as well, but I'm not sure anymore.
OK, after using common emitter will current also increase?An emitter-follower has a VBE voltage drop that causes the transistor to get hot and restricts the supply voltage to the signal voltage (5V from a micro-controller).
A common-emitter transistor does not have these problems. But the base current for a bipolar transistor will be higher than you have available.
As i am using PIc16F877a so, without base resistance it will damage it..Maybe he used a pot on the base because he didn't read the datasheet for the transistor, where it says the base current must be 1/10th the collector current for fairly good saturation at high currents.
Do not operate the BC337 transistor at its maximum collector current because it works poorly above 200mA.OK, I have noticed this in data sheet: that mean i have to raise the base current as pic16f is not giving sufficient current so, so using another transistor at base like bc547 will be fine??
VCE (sat) Collector-Emitter Saturation Voltage IC=500mA, IB=50mA 0.7 V
Why is the emitter of the BC547 at 5V? A BC547 can be an emitter-follower to drive the base of the BC337 with its emitter.PIC16f output to 5K base resistance of BC547 and its emitter to Vcc of 5V and collector to 10K pott. meter at base of BC337 and emitter to gnd and collector with 55Ohm 2watt series resistance to led...
You did not post a new schematic so I do not know what you are talking about.OK, after using common emitter will current also increase?
Ohm's Law says that two resistors with the same value in parallel double the current and double the power if the voltage remains the same.I have doubt using in // resistance of same value will double the power??
why???Do not operate the BC337 transistor at its maximum collector current because it works poorly above 200mA.
Awhy???
why common collector in reversed biased switching?Why is the emitter of the BC547 at 5V? A BC547 can be an emitter-follower to drive the base of the BC337 with its emitter.
What is "reverse biased switching"?why common collector in reversed biased switching?
the viewing angle problem, anyway how to make equal?It is obvious that each LED has a different brightness. Some LEDs look like they are turned off and other LEDs look like they are ready to burn out.
Just like we told you!
LEDs in parallel MUST all be measured then only the few with IDENTCAL forward voltages can be connected in parallel.how to make equal?