Hello all,
I know this may seem like a simple topic but I have looked at all the tutorials I have found and am still very lost, maybe i need a new perspective, I have a circuit that I designed a while ago. a 9V source as a battery, a microchip processor sending out roughly 5V signals to turn on and off several transistors for different pins. 3 LEDS in Parallel(1.8V @ 20mA) just fo this example and I am lost with the calculations of the resistors and how I can drive these with the correct voltage and current. I have also tried transistor calculators but they have yet to help me. I will include a picture of the transistor part if I am able. The transistor I am using is a BSR43 SOT89 NPN Transistor I got from digikey.com
Hopefully you will be able to explain how to get the right values so I can do this on my own soon. I have other values of leds I need to light up so its not just going to be the 1.8Vx20mA
Thanks in advance
I know this may seem like a simple topic but I have looked at all the tutorials I have found and am still very lost, maybe i need a new perspective, I have a circuit that I designed a while ago. a 9V source as a battery, a microchip processor sending out roughly 5V signals to turn on and off several transistors for different pins. 3 LEDS in Parallel(1.8V @ 20mA) just fo this example and I am lost with the calculations of the resistors and how I can drive these with the correct voltage and current. I have also tried transistor calculators but they have yet to help me. I will include a picture of the transistor part if I am able. The transistor I am using is a BSR43 SOT89 NPN Transistor I got from digikey.com
Hopefully you will be able to explain how to get the right values so I can do this on my own soon. I have other values of leds I need to light up so its not just going to be the 1.8Vx20mA
Thanks in advance
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