2N2222A current buffer circuit

[ahmedg]

i need to amplify an IC output signal current using 2N2222A need help with the connections??

 

[HarryA]

If you search on the following and click on the link for Hunter college you get a lesson on using the 2n2222 that maybe helpful:
"15. Transistor Amplifier Design and Measurement"
I can not pass the url for some reason as it links to a pdf file.

edit: well I guess it does work here

 

[BobK]

You need to tell us what you are trying to do. Signals are not usually currents (though they might be). Are you talking about linear amplification (duplicating a waveform) or are you just talking about using a digital signal to turn something on or off?

Bob

 

[ahmedg]

using a digital signal on and off but the IC output signal won't operate the mosfet so i had to amplify it using a bjt so i need to know kan i use a 12v 1 amp as Vcc and the value of the Rc

 

[ahmedg]

can i use this voltage follower circuit as a current amplifier because i don't have any problems with the voltage?

 

[BobK]

MOSFETs are voltage operated and do not need any appreciable current, so you still are not describing the problem correctly.

What is the voltage of the signal when ON and when OFF?

Most likely, a logic level MOSFET is what you need. These can be turned on with voltages in the 3-5V range.

Bob

 

[ahmedg]

i knew it but the electronics store guy put this current idea into my head i'm using IRF1010E which has gate threshold voltage at 2v and the output of the IC ranges between 3.5-3.8 but i measured the mosfet output and it was 0 v using a 12v 1amp adaptor as a Vcc on the Source pin of the mosfet. thanks for your help

 

[BobK]

i knew it but the electronics store guy put this current idea into my head i'm using IRF1010E which has gate threshold voltage at 2v and the output of the IC ranges between 3.5-3.8 but i measured the mosfet output and it was 0 v using a 12v 1amp adaptor as a Vcc on the Source pin of the mosfet. thanks for your help

Show us a circuit.

2V is the minimum theshold voltage. You need to go by the max, which is 4V. And at the threshold voltage, it only passes 250uA.

And the source should be connected to ground, no Vcc.

Bob

 

[ahmedg]

so this is the timer circuit and i have the output to the gate of the mosfet and its Vcc is 12v,1amp and i should get 12 v output to operate a 12v solenoid valve (there is no led or 330 ohm at the output did it for testing the output of the IC)

 

[ahmedg]

how to i connect the source to ground while i need 12v (using the mosfet as a switch)

 

[(*steve*)]

how to i connect the source to ground while i need 12v (using the mosfet as a switch)

You place the load between Vcc (or Vdd in this case) and the drain.

 

[ahmedg]

ok so source is ground
gate has the input voltage
and load between drain and vcc
right?!!!

 

[(*steve*)]

That is typically how it's done.

You might add a resistor (say 100k) between gate and source to ensure that the MOSFET remains in the off state when power is not applied.

 

[ahmedg]

thanks steve it worked with no resistances the deadline is in two hrs