2n2222

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watzmann

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please check this schematic may be i have something wrong , i'm going to make it's PCB,

the function of this board is to get a signal from PIC16f877 main board and run H-Bridges and other circuits which required 5V or 12 Volt but with more tolerance with the current

i'm using 2n2222


thank you
 

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Looks fine, most use a ULN2803 to do the same thing as it has the diode clamps and higher gain than the 2N2222A plus a nice simple DIP package.
**broken link removed**
 
Your circuit doesn't have resistor values nor does it have a load. So it might work, it might not work or it might blow up.

If it is designed properly:
When an input is high then the output of a transistor is low.
When an input is low then the output of a transistor is high.
 
actually i don't know how yo use this ULN2803 , but i'll download it's datasheet and i'll try to understand it .

if you can help please tell me , what is this circus , it looks like stepper motor
 
looked at the datasheet , my question is :

the output is just 500mA and 50 Volts

how to increase this 500 mA , it's so low
 
watzmann said:
looked at the datasheet , my question is :

the output is just 500mA and 50 Volts

how to increase this 500 mA , it's so low
Click to expand...
In that case the 2N2222 isn't that much more powerful at 800ma and you'll need to drive it fairly hard to get that and it will get very warm. A TIP112 darlington might be a better idea.
500ma is generally enough for many small stepper motors.
 
Last edited:
i don't need to drive stepper motors , but i just have four H-Bridge circuits which drives 4 DC motors , i think each one about 1A,

for that raeson i'm asking for more current.

as for the TIP 112 should i use a buffer before connecting it with the pic
 
hi,
The TIP122 is a medium power npn darlington, with a gain of about 1000.

For TIP122 collector currents of about 2amps or so, all you need is a PIC pin to TIP 122 base resistor, say about 270R.
 

Better to use a SN754410 Quad Half Bridge. 1.2A with thermal shutdown, nice part. Of course larger ICs exist and will save you burning out transistors. Your original 2N2222 circuit is not an H-Bridge, you'll need PNP transistors too for a proper H-Bridge.
 
Unlike good Mosfets, darlington transistors have a voltage loss. An H-bridge made with darlingtons could have a loss of up to 6V.

A "1A" motor draws 10A or more when it starts and when it is stalled.

Try this H-bridge that uses darlingtons:
 

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blueroomelectronics said:
Your original 2N2222 circuit is not an H-Bridge, you'll need PNP transistors too for a proper H-Bridge.
Click to expand...

Yes my original circuit 2n2222 is not an H-bridge , it's just a connection between the PIC main control circuit and the H-bridge ,

my H-bridge is working very well and up to 1.5A,

but i'll try the new one as it's for 5A , may be i need that capacity later
 
This circuit uses N-channel and P-channel Mosfets.
 

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