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@p.gholap93
But according to the data sheet, we have to select 330 ohm resistor. if you check the datasheet of transistor. But ithink you are also right that small base current can also take the transistor into saturation.
Didn't you know that the NPN transistor inverts the logic? Without the transistor, the LEDs light dimly when the output of the microcontroller goes low. With the transistor, the LEDs light brightly when the output of the microcontroller goes high.
To have the same logic as before, you could drive the anodes of the LEDs from a PNP transistor then the cathodes of the LEDs are connected to ground. Then the LEDs will light brightly when the output of the micro controller goes low.
connect o/p of micro controller through 1kΩ resistor to base of transistor.also on the collector side increase the series resistor from 100Ω to 220Ω.I think, this happens because even a very small base current can drive transistor into saturation unless base resistor is connected.
@p.gholap93
But according to the data sheet, we have to select 330 ohm resistor. if you check the datasheet of transistor. But ithink you are also right that small base current can also take the transistor into saturation.
are you asking me that if i used the PNP transistor? No, i did not use the PNP transistor.
actually i am a bit tensed for the remote. i have make it fix it, so i don't have to tune it after every minute. please help me regarding that.
The circuit has serious errors and uses old and garbage parts. The remote control decoder is a cheap old Chinese RX-2B IC made for cheap toys for children.
The circit even uses a very old 7404 IC.
There are many better Propeller Clock circuits on the internet.
You can fiddle around with the frequency adjustment of the RX-2B decoder IC that was designed to be used in a children's toy.
Or you can find a much better circuit.
Thanks a lot every One, who helped me in my project. i was reading this thread And enjoyed my errors and mistakes and how much i teased you all guys
Thanks every One Specially AudioGuru.
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