15 April 2014

JFET measurements continued

Since I am now getting ready to build the second oscillator for the RF signal source (10MHz - 45MHz) I thought it would be instructive to test a few more MPF102's for this oscillator. The same test fixture was used as previous (see Label JFET Experiments). Results as follows:

Vd-d = 10.04V

SAMPLE     Idss (mA)    Vp (Volts)
1B                  9.8              -2.75
2B                  7.3              -2.83    
3B                  9.98            -3.51
4B                  9.2              -2.4

Sample 4B was a re-measure of the previous Sample 1 and yielding similar results. Tests were carried out quicker this time to minimize the effects of sample heating with the smaller resistance range.

Sample 3B has the widest dynamic range between Vp and Idss. Start with that sample in the oscillator and then measure the output when compared to sample 4B which is the most linear.

Sample 1B
Sample 2B
Sample 3B

Sample 4B

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