Whites Surf PI schematic

[Davor]

tpx is a common notation of "tuning point", e.g. a place where you stick an oscilloscope probe to get more confused

[nando.22]

what goes on in the circuit tp1

[kt315]

SFS9634 p-channel, 250V, 3.4A, 1.8Ohm - SFP9634, 2SJ307, 2SJ308, 2SJ449
2SJ448 NEC Electronics Inc Downgrade Active
FQPF6P25 Fairchild Semiconductor Corp Downgrade Active
FQPF7P20 Fairchild Semiconductor Corp Downgrade Active
SFS9640 Fairchild Semiconductor Corp Downgrade Active
SFS9640 Samsung Electronics Inc Downgrade Active
SFS9644 Fairchild Semiconductor Corp Downgrade Active
SFS9644 Samsung Electronics Inc Downgrade Active
2SJ306 - 2SJ307, 2SJ308, 2SJ449, IRFI9634G, SFS9634, SFP9634

[nando.22]

to replace the TIP32 by TIP42

[nando.22]

which transistor can use in place of irf 9640

[mahavir]

Hi friends,
I am from India (maharashtra). I'm studying at diploma in electrical engg.
I made pi detector but they have no good deep range so plz help which is best for gold nuggets and they have good deep rang (minimum 3 foot/36 inch)
Thanks,

[porkluvr]

take lt 1115.
can anybody say wether the curve posted above is ok

regards

That damping resistor might be OK for the coil but the flyback looks like ~70us duration to settle (310us-238us).

Did you have the coil resting near something metallic?

[TH Jim]

Hi Bernte,

There are a few posts on here that show curves similar to yours I think (i may have posted a few myself). Have a look and compare yours to those.

It's been a while since i looked at a PI curve!

Regards, Jim.

[bernte_one]

take lt 1115.
can anybody say wether the curve posted above is ok

regards

[Davor]

NE5534 is offset compensated against the positive, while TL071 is compensated against the negative rail. And not at the same pins.
NE5532 does not have offset compensation as 5534 does. The offset could be tweaked by adjusting the resistance at the inverting input, however, increasing it would spoil noise performance.
TL071 is much noisier than 5534.

[nando.22]

What changes should I do to replace the ne5534 tl071

[ppodg]

Just compare the datasheets step by step...

[nando.22]

NE5532 may be used in place of ne5534

[Jose]

NE5532, contains two (2) internal amplifiers.
NE5534, contains only 1 (one)
Jose

[nando.22]

NE5534 and NE5532 are similar