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Transistors Difference

oskar270

Member
The attached schematic indicates how to build an electromagnetic coil for a wooden clock I’m building. however my local store did not have the required 2N2222 transistor and they gave me a 2N222A.

Does it make a difference?

Thanks
 

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ljcox

Well-Known Member
Did you mean 2N2222A? If so it is the same transistor. Virtually any NPN transistor should suffice provided it can handle the collector current.
 

oskar270

Member
Thank you for your time Len

I was told at the store it is 2N222A but looking at it now with magnifying glass it says

KSP 2222A K3g

Should I test it and if yes how? I will be using 9VDC and my meter
 

AnalogKid

Well-Known Member
Most Helpful Member
2N2222, 2N3904, 2N4401, etc. In your application, electrically identical. BUT - check the pinouts.

ak
 

atferrari

Well-Known Member
The schematic was listing also a 2N3???
 

ljcox

Well-Known Member
Does your meter have a transistor tester option?
Do you have a data sheet for the 2N2222? Also look search for the KSP 2222A . Compare their data sheets. I suspect it is identical to the 2N 2222A.
If not, you can download them from the internet.
Does your meter have a diode option?
If so, check the Base - Emitter junction & the Base Collector junction they should both measure the same as a diode. i.e about 0.6 Volt in the forward direction & open circuit in the reverse. (identify the C, B & E legs from the data sheet)
You could also rig up a simple test circuit using a 9 Volt battery & 2 resistors. Use what ever you have on hand for the collector resistor. A resistor between 1k & 10k would suffice. Connect the other end to the +9 Volt battery (& the emitter to the - terminal. Measure the voltage across the C & E. It should read about 9 Volt. Then connect another resistor (10 k ~ 33 k) between the B to the +9 V. The C voltage should drop to less than 1 Volt.
Do NOT connect the B directly to the +9V. Let me know how you go.
 

oskar270

Member
Of course I’m aware with the pinouts, most important

Len my meter does not have a transistor or diode options. From the Internet I understand the 2222A is the newer version of the 2222 so I think I’m ok.

My collection of electronic supplies is very limited and unfortunately one of the 2 bridges (Ile Aux Tourtes Bridge) connecting my area to the Montreal island is closed indefinitely since yesterday afternoon. The traffic is diverted to a second smaller bridge and it took me today 4 hours to go and get the transistor. Since the electronics supply store is in Montreal I can’t go again to get the resistors required to complete the test you are suggesting. It’s much easier to complete the electromagnetic coil.

I ordered the 30g wire for the two coils thru Amazon and I should get it on Monday

My thanks to all
 

crutschow

Well-Known Member
Most Helpful Member
The 2N2222a will be fine for you circuit.
You don't need to test it.
 

unclejed613

Well-Known Member
Most Helpful Member

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