[sdiy] variable width pulse wave for JEFT sample and hold

[Ian Fritz]

Or use Bernie's S/H technique.  Fire a 555 timer powered between 0V and -15V.


At 11:19 AM 1/6/2009, David G. Dixon wrote:

>Why not just use an RC high-pass filter with a time constant of about 10 us
>to generate spikes from the square (0.001 uF and 10 k will do nicely), and
>then shift the pulses with a unity-gain inverting opamp with a voltage 2:1
>divider off the positive input between -15V and 0V so that the output DC
>rides at about -5V and the spikes go up to 0V to trigger the JFET (which, I
>presume, is npn and therefore is full off at about -3.5V and full on at
>about 0V)?