Hi,
I have been working to make a very simple circuit work but have not been successful. I tried to simulate it using multisim and also tried it on a breadboard. I am wondering if anyone could help me with this. The circuit consist of an opamp, a phototransistor and some LEDs. Please have a look at the schematic from Multisim. The LEDs are supposed to be on or off one by one depending on light.
Please see also the external source links for this circuit.
**broken link removed**
Link 2
In both of the links one can easily notice that the only base and collector of the transistor have been used. That means one needs to have a phototransistor with three legs whereas I am using a phototransistor which has only two legs i.e. emitter and collector. This leads me to two questions.
Question 1: Can such a circuit be realized with a transistor which has only two legs i.e. collector and emitter? If yes what adjustments have to be made in order to make it function properly?
Question 2: Since the circuits in link 1 and link 2 both are employing only base and collector of the transistor isn't the transistor being used as a photodiode instead of phototransistor? If the transistor is being used as a photodiode why the symbol of photodiode is not mentioned? Can a photodiode be used instead?
In addition I have an additional question.
Question 3: The circuit in link 1 shows that both collector and base (almost) are grounded. How that works?
Thanks
I have been working to make a very simple circuit work but have not been successful. I tried to simulate it using multisim and also tried it on a breadboard. I am wondering if anyone could help me with this. The circuit consist of an opamp, a phototransistor and some LEDs. Please have a look at the schematic from Multisim. The LEDs are supposed to be on or off one by one depending on light.
Please see also the external source links for this circuit.
**broken link removed**
Link 2
In both of the links one can easily notice that the only base and collector of the transistor have been used. That means one needs to have a phototransistor with three legs whereas I am using a phototransistor which has only two legs i.e. emitter and collector. This leads me to two questions.
Question 1: Can such a circuit be realized with a transistor which has only two legs i.e. collector and emitter? If yes what adjustments have to be made in order to make it function properly?
Question 2: Since the circuits in link 1 and link 2 both are employing only base and collector of the transistor isn't the transistor being used as a photodiode instead of phototransistor? If the transistor is being used as a photodiode why the symbol of photodiode is not mentioned? Can a photodiode be used instead?
In addition I have an additional question.
Question 3: The circuit in link 1 shows that both collector and base (almost) are grounded. How that works?
Thanks