Hello,
6 months ago I applied myself to learn a little about transistors. I took a lot of notes and you guys were great help. Still far from being an expert though!
Now, 6 months later, I require the use of a transistor to convert a CPLD 3.3/0VDC signal to 4.0/0 VDC signal as follows:
Square wave signal coming out from CPLD: 3.3-0VDC
connvert to:
Square wave signal of: 4.0-0VDC
Therefore, I decided to use a 2n2222 transistor. After testing and calculating with simple formulas I came out with the following circuit in the attachment.
The way I did this was I set the requirements as:
- Let IR1 be 1ma
- Let VR1 be 1V
- Let VR2 be 4V
- Let Beta be 100 (Even though we know beta can vary)
- Let Vbe be 0.7V
- Let IR3 be 30 times the Ic/Beta current (Sorry 10 times didn't quite cut it)
R1 = 1V/1ma = 1K
R2 = 4V/1ma = 4K
IR3 = (Ic/Beta)30 = (1ma/100)30 = 300ua
R3 = (3.3-0.7)/300ua = 8.6K = didn't have !!! used a 7.1K
The components values I used in my attachment given by the above calculations works very fine.
-Questions:
1) My question is, did I use the correct circuit configuration to do this or is there a better way?
2) As you may have noticed my circuit is also an invertor. Is there a way to make my circuit (Just using one transistor) do the the same voltage conversion without the inversion?
3) I am getting 0.13VDC when the base is 3.3V. Shouldn't I get a better groung like somewhere around... 0.04VDC???
Thanks all feedback appreciated!
r
6 months ago I applied myself to learn a little about transistors. I took a lot of notes and you guys were great help. Still far from being an expert though!
Now, 6 months later, I require the use of a transistor to convert a CPLD 3.3/0VDC signal to 4.0/0 VDC signal as follows:
Square wave signal coming out from CPLD: 3.3-0VDC
connvert to:
Square wave signal of: 4.0-0VDC
Therefore, I decided to use a 2n2222 transistor. After testing and calculating with simple formulas I came out with the following circuit in the attachment.
The way I did this was I set the requirements as:
- Let IR1 be 1ma
- Let VR1 be 1V
- Let VR2 be 4V
- Let Beta be 100 (Even though we know beta can vary)
- Let Vbe be 0.7V
- Let IR3 be 30 times the Ic/Beta current (Sorry 10 times didn't quite cut it)
R1 = 1V/1ma = 1K
R2 = 4V/1ma = 4K
IR3 = (Ic/Beta)30 = (1ma/100)30 = 300ua
R3 = (3.3-0.7)/300ua = 8.6K = didn't have !!! used a 7.1K
The components values I used in my attachment given by the above calculations works very fine.
-Questions:
1) My question is, did I use the correct circuit configuration to do this or is there a better way?
2) As you may have noticed my circuit is also an invertor. Is there a way to make my circuit (Just using one transistor) do the the same voltage conversion without the inversion?
3) I am getting 0.13VDC when the base is 3.3V. Shouldn't I get a better groung like somewhere around... 0.04VDC???
Thanks all feedback appreciated!
r
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