# circuit design

by chemic_23
Tags: circuit, design
 P: 45 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 dont 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)
 P: 5,462 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.
 P: 28 circuits drawn wrongly, in both 0v & +6v terminals are shorted on left side. in 1st circuit lamp terminals are shorted?
P: 5,462

## circuit design

 Quote by aks786 circuits drawn wrongly, in both 0v & +6v terminals are shorted on left side. in 1st circuit lamp terminals are shorted?
Yes good catch.
 PF Patron Sci Advisor P: 10,109 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.
 P: 45 o, i see, sorry i've overlooked that.. thanks.. um, btw, can i use KN2222 transistor instead of 2N2222? are they the same?
Mentor
P: 37,655
 Quote by 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?
You should compare their datasheets. That's what we would do.

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