Author Topic: P Version for 2N5457, j201, mpf102  (Read 624 times)

spoontex

P Version for 2N5457, j201, mpf102
« on: January 22, 2022, 11:52:48 AM »
Anyone knows the P Channel version for this transistors?

2N5457
J201
MPF102


Thanks.

rankot

Re: P Version for 2N5457, j201, mpf102
« Reply #1 on: January 22, 2022, 12:13:02 PM »
If you're looking for complementary pairs, no AFAIK. PJFET are actually rare.
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pacealot

Re: P Version for 2N5457, j201, mpf102
« Reply #2 on: January 22, 2022, 12:43:55 PM »
I have found some 2N5460s that spec out somewhat closely (JFET relative, of course) in terms of VP and IDSS to the 2N5457, but I'm not aware of of "complements" to the other two. If they need to "match," you might be in for a long hunt, as Ranko indicates. The J175 might get you close-oid to the MPF102, if by "close" one means in the manner that Jupiter is "close" to Saturn.  :)  JFETS are really something else. Good luck!
"Stupidity has a certain charm; ignorance does not." Frank Zappa

"I hate guitar players. Whatever." Scott Thunes

spoontex

Re: P Version for 2N5457, j201, mpf102
« Reply #3 on: January 22, 2022, 12:57:51 PM »
Thanks.

I want to experiment with buffers and positive ground effects.

I will have a look.

antonis

Re: P Version for 2N5457, j201, mpf102
« Reply #4 on: January 22, 2022, 02:24:50 PM »
I want to experiment with buffers and positive ground effects.

No offence but buffers don't mind about transistor channel carries and ground "faces" JFETs Drain & Source indiscriminately.. :icon_wink:
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

spoontex

Re: P Version for 2N5457, j201, mpf102
« Reply #5 on: January 22, 2022, 02:44:58 PM »
I want to experiment with buffers and positive ground effects.

No offence but buffers don't mind about transistor channel carries and ground "faces" JFETs Drain & Source indiscriminately.. :icon_wink:

No offence, don't worry about that! Can I use a N Jfet with positive ground? I need to learn something about jfet's...

Thanks.

antonis

Re: P Version for 2N5457, j201, mpf102
« Reply #6 on: January 22, 2022, 03:07:53 PM »
Can I use a N Jfet with positive ground?

As far as VGS = 0 V and Drain - Source are interchangeable, proceed without any reservation..
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

spoontex

Re: P Version for 2N5457, j201, mpf102
« Reply #7 on: January 22, 2022, 03:17:30 PM »
Can I use a N Jfet with positive ground?

As far as VGS = 0 V and Drain - Source are interchangeable, proceed without any reservation..

Thanks.

antonis

Re: P Version for 2N5457, j201, mpf102
« Reply #8 on: January 22, 2022, 03:27:56 PM »
Sorry for my laconism but you'll have to study a bit JFETs curves vs BJTs ones.. :icon_wink:
(in the mean of BJTs are strongly dependent both on power supply polarity and p-n or n-p junction boundary where JFETs are only prone to VGS sign/value..)
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

spoontex

Re: P Version for 2N5457, j201, mpf102
« Reply #9 on: January 22, 2022, 03:34:57 PM »
Sorry for my laconism but you'll have to study a bit JFETs curves vs BJTs ones.. :icon_wink:
(in the mean of BJTs are strongly dependent both on power supply polarity and p-n or n-p junction boundary where JFETs are only prone to VGS sign/value..)

I need to study a lot of things...  :icon_redface: hehe. Thanks!

anotherjim

Re: P Version for 2N5457, j201, mpf102
« Reply #10 on: January 23, 2022, 05:39:02 AM »

To convert to positive ground, you have to sort out the connections for correct polarity for the active device (your N JFET) and actual ground which will now be the positive supply rail.

Starting at the top, +9v will now be ground.

Volume pot ground will stay at ground. The 22n cap removes DC to the pot so polarity doesn't need to change. If that cap was are larger electrolytic, its polarity would need reversing.

The 1M gate resistor and the 1k5 source resistor change from ground to -9v to suit the N-channel device.

The 22uF source bypass cap reverses polarity and stays connected to ground. It could stay the same polarity and connect to -9v instead of ground, however, it must really connect to the true circuit ground via a low impedance path to that ground and that is now the positive supply.

The biggest change is due to the gate voltage now being referenced to -9v instead of ground, so we now have DC voltage on the circuit input that needs to be removed. So you must add a series input cap into the 68k "grid stopper", 10nF will do.

« Last Edit: January 23, 2022, 04:54:46 PM by anotherjim »
Croeso i Diystompboxes.

I have no April 1st project

duck_arse

Re: P Version for 2N5457, j201, mpf102
« Reply #11 on: January 23, 2022, 09:33:22 AM »
Jim, can you see a circuit dia in this thread that I can't? cause I can't.

[edit: sorry I missed the party for 5000, too.]
« Last Edit: January 23, 2022, 09:56:46 AM by duck_arse »
by request

anotherjim

Re: P Version for 2N5457, j201, mpf102
« Reply #12 on: January 23, 2022, 04:55:32 PM »
Ah, the HHTP didn't have no S. Fixed now?
Croeso i Diystompboxes.

I have no April 1st project

duck_arse

Re: P Version for 2N5457, j201, mpf102
« Reply #13 on: January 24, 2022, 08:54:50 AM »
excellent. now we can have a 5007 party.
by request