Determining Part Number for NPN Transistors

[chemic_23]

hello good day, would someone kindly help me determine the part number of these 4 npn transistors here? pls help, cause my prof didn't discuss this yet.. and i don't have idea on how to calculate for the values of the transistor to determine tha part number suitable for the circuit... many thanks (um this isn't homework by the way)

 

[Studiot]

Hello, I take it you understand that the transistors are NPN>

Pretty well any small or medium signal NPN transistor will do here, they do not even have to be of the same type.

Common Suitable types might be

BC547/548/549
2N2222(A)
2N3704
2N3904
MPSA42/43
2SC1318

Remember these have different pinouts or connection arrangements so make sure you know the one for the transistor you actually use.

 

[aks786]

circuits drawn wrongly, in both 0v & +6v terminals are shorted on left side. in 1st circuit lamp terminals are shorted?

 

[Studiot]

circuits drawn wrongly, in both 0v & +6v terminals are shorted on left side. in 1st circuit lamp terminals are shorted?

Yes good catch.

 

[sophiecentaur]

You should detach the 'Earthy' end of those lines and use 1k 'pull down' resistors after the switches if you want to really define the states of the input signals.

 

[chemic_23]

o, i see, sorry I've overlooked that.. thanks.. um, btw, can i use KN2222 transistor instead of 2N2222? are they the same?

 

[berkeman]

o, i see, sorry I've overlooked that.. thanks.. um, btw, can i use KN2222 transistor instead of 2N2222? are they the same?

You should compare their datasheets. That's what we would do.