[sdiy] MOSFET instead JFET?

[oleavitt at ix.netcom.com]

I too, have thought about about trying MOSFETs as an integrator reset switch in a current-controlled sawtooth osc.
I haven't tried it yet, but I have had very good results with the following N-channel JFETs: NTE-466, NTE-467 (Formerly ECG)
Datasheets (PDF):
http://www.nteinc.com/specs/400to499/pdf/nte466.pdf
http://www.nteinc.com/specs/400to499/pdf/nte467.pdf

The 2N4391/2 JFETs work good, but lag a bit on the turn-on time.

Some JFETs marked 'u1897' that I found in my local surplus electronics store also worked very well.

Piggy-backing two JFETs in paralell also speeds discharge time - Any added leakage didn't seem to be significant.

My two-bits..

Regards, Oren Leavitt

">>>marjan<<<" <urekar.m at EUnet.yu> wrote:
> 

I was looking at mosfet datasheet (BS170), it's Ron=5 ohm, nice it is,
has anyone tried it instead jfet in VCO (for cap discharging), maybe
just
few changes to original ccts?
Is there something crucial that prevents us from using mosfets in this
way 
that I don't see?

-- 



marjan


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