In answer to your HFE accuracy question, the HFE is measured to an accuracy of nominally ±3%.
I hope that helps,
Jez
Just for the record, it is
hFE and
hfe, just two of the many " h" or hybrid parameters that excist.
The first is the DC amplification of a common emitter amplifier (F=forward, E= common emitter, capitals is DC ) and I think this is what the peak measures. The other one is the result of delta Ic to delta Ib, sometimes called small signal amplification. At DC the amplification can be 100 but at some frequeny, called Ft, the gain is dropped to 1 so if your peak shows you a gain of 100, this will not say this transistor has still a gain of 100 in your application at 10 MHz. But Datasheets show it so it is just a test. I have seen transistors with a perfect gain at a steady Ib, but an increase of Ib did not give a single reaction. This was while repairing an old HP. The Peak and some transistor testers told me it was good. The scope told me there was a problem. The Tek curvetracer showed me the real problem. But these are exeptions, just to tell you, never trust any instrument without thinking or cross checking.
hfe is a bit more difficult to measure.
From the wiki:
https://en.wikipedia.org/wiki/Bipolar_junction_transistor#h-parameter_modelEtymology of hFE[edit]
The 'h' refers to its being an h-parameter, a set of parameters named for their origin in a hybrid equivalent circuit model. 'F' is from forward current amplification also called the current gain. 'E' refers to the transistor operating in a common emitter (CE) configuration. Capital letters used in the subscript indicate that hFE refers to a direct current circuit.
http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=1446653&url=http://ieeexplore.ieee.org/iel5/5/31082/01446653.pdf%3Farnumber%3D1446653Both the ESR60 and ESR70 have the same measurement resolution of 0.01 Ohms and this is measured at the "industry standard" of 100kHz that most capacitor manufacturers like to specify.
This is not complete true. Most manufactures state |Z| at 100kHz and ESR as a function of D at 1 kHz or 100/120 Hz. Z = impedance = (R -jX) or ( ESR and reactance). reactance = 1/(2pifC) and ESR = D x reactance
Because at 100kHz the jX of Z is neglectible for large enough caps, ESR will be the main part of Z. My home made ESR meter measures down to 100 nF and even lower. A very good 1 nF cap with a low D of 0.001 has an ESR at 1 kHz of 159 Ohm. So that is why it is more convinient to measure at higher frequency. But you can not measure C with 100 kHz because the appearant capacitance there differs a lot from the true capacitance. That is why 100 Hz and 1 KHz will stay standards for measuring C
But if capacitance is dropped a lot, Z will be higher. An impedance meter shows you there is "some" problem. But not if it is ESR or capacitance. The peak will only show the ESR and that can in some rare cases (got some samples here) still be good . And because the peak measures C using DC it will show a high capacitance so it seems like that cap is still good. But again, for 95% of the cases it performs very good and is a nice help next to your standard scope probing for ripple curents.
I tested some power MOSFETs a while back in Ton and Toff and beside a function of Vgs this is also a function of Id and Vds. A 600V 20A Fet is a lot slower at 15V and 1A