Logic Level Converter

[Mamdouh1]

hello All EDABOARD .
Can any one replace (BS170) by (BC547) in this attached circuit ? or any circuit use BC547 , to make Bi-direction logic level converter .

there is any way to do it .
thanks

 

[FvM]

No. A bipolar transistor doesn't conduct current in both directions.

 

[Mamdouh1]

Thanks
Are there any another Logic Level Converter circuit even if it used two transistor BC547 ?

 

[FvM]

I have to correct myself. A single BJT can be used if transistor reverse operation is utilized. Reverse current gain is limited to about 1, so the pull-up resistor at the 3.3V bus must not be too low. Instead R1 is supporting the pull-up action.

 

[Mamdouh1]

Thanks for fast reply.
but my main problem is limited electronic distributor in my country ,so i need if possible get circuit base in BC547 , BC548 , BC546 , BC556 or 2N2222 .
I found this circuit but i don't know if it is work as should be ,or how test it .
Thanks again , and sorry for bad English .

 

[FvM]

The circuit isn't very different from the single transistor circuit. I first started with the same idea and then realized, that a single transistor should do the trick. A problem is, that the current sharing between both transistors (one in forward, one in reverse operation for both directions) isn't well defined. You can improve it by using separate base resistors.

I would go for the single transistor circuit. It works well in SPICE simulation.