Question about transistor substitutions.

In most circuits could a 2n3904 be used in place of a 2n4401, and a
2n3906 in place of 2n4403? 906 is the pnp and 904 is npn, right?

 

[Jonathan Kirwan]

On 21 Aug 2005 10:15:09 -0700, ngdbud@hotmail.com wrote:

In most circuits could a 2n3904 be used in place of a 2n4401, and a
2n3906 in place of 2n4403? 906 is the pnp and 904 is npn, right?

The 3906 is a PNP and the 3904 is an NPN. So yes. Also, the 4401 is
an NPN and the 4403 is a PNP. I'd imagine that for most common
purposes, the NPNs and PNPs could be exchanged for each other. Their
forward betas are similar, junction capacitances aren't too far apart,
etc.

Jon

 

[Jonathan Kirwan]

On Sun, 21 Aug 2005 18:10:33 GMT, Jonathan Kirwan
<jkirwan@easystreet.com> wrote:

In most circuits could a 2n3904 be used in place of a 2n4401, and a
2n3906 in place of 2n4403? 906 is the pnp and 904 is npn, right?

The 3906 is a PNP and the 3904 is an NPN. So yes. Also, the 4401 is
an NPN and the 4403 is a PNP. I'd imagine that for most common
purposes, the NPNs and PNPs could be exchanged for each other. Their
forward betas are similar, junction capacitances aren't too far apart,
etc.

Just to be clear about it, I meant "the two NPNs could be exchanged
for each other and the two PNPs could be exchanged for each other."

Jon

 

I figured, thanks your help! you just saved a penny pincher from
spending an extra dollar or two.

 

[Ralph Mowery]

<ngdbud@hotmail.com> wrote in message
news:1124644509.403689.258840@z14g2000cwz.googlegroups.com...

In most circuits could a 2n3904 be used in place of a 2n4401, and a
2n3906 in place of 2n4403? 906 is the pnp and 904 is npn, right?

In most common circuits operating below a megacycle or so you can subistute

just about any transistor that is any where close to the origional
transisitor. The operating conditions are mostly set by the external
components. You only get into trouble if it is special such as low noise
or high gain. Just watch the voltage and power ratings of the transistor.