Hi guys !
I`m glad to join this forum. I`m sure I can find a lot of people from which I can learn.
My riddle is the following :
I`m trying to do a project at my college, using a laser pointer, a fiber optic cable and a receiver. The problem is that I have to explain the circuit in the receiver and I don`t know it completly.
So here are some pictures :
Ok, so from what I understand the circuit goes like this :
Thanx !
Andrew.
I`m glad to join this forum. I`m sure I can find a lot of people from which I can learn.
My riddle is the following :
I`m trying to do a project at my college, using a laser pointer, a fiber optic cable and a receiver. The problem is that I have to explain the circuit in the receiver and I don`t know it completly.
So here are some pictures :
Ok, so from what I understand the circuit goes like this :
- First, the light transmitted via the fiber optic is used to power a Photodiode which actually does this process of conversion between light and voltage.
- Second, the voltage is amplified with an Op-Amp, powered by pins nr. 3-Vcc respectively 2-Gnd, which also have a bypass cap for noise.
- The output from the Op-ams is then used to control the base current of an npn transistor, wired in the collector-emitter configuration.
- Which is the role of the RL - the pull up resistor - as it is parallel connected and obviously the current from Vcc won`t be limited by it when it goes to the Op-Amp and why do I connect it together with the output voltage - Vo ?
- How come that I get 5V when there is no light through the fiber and 0V when the fiber has light through ? How exactly does the transistor work ?
Thanx !
Andrew.