[SOLVED] Esr meter by bob parker

[pgr2002]

The ic z86e0408/0412 used in the mk2 esr meter by bob parker is not available. Can anybody tell what could be the best and workable replacement of this ic.

 

[D.A.(Tony)Stewart]

The best uC is the one you know how to use.

But basically the ESR meter measures the pulsed voltage drop for a high current limited pulse using a switched PNP or a MOSFET after it has been discharged with an NPN or MOSFET to ground.

The auto ranging firmware would start with smallest pull-up switched resistor and then discharge then next enable next decade higher R until output is more than 10% of full scale. This forms a bridge between the pullup R and the internal ESR of cap. Setting time is required in firmware or a sample and hold in hardware,

but there is no reason you could not do this without uC and use logic to control pulsed switches and DMM.



With advances in low ESR capacitors down to <10 milliOhms these days, I would change this design to very low RdsON Mosfets, then add more decade ranges of smaller R pullup like 1 Ohm and 0.1 Ohm. Then more serious filtering of supply.

 

[Allen6502]

The chip is available from Element 14. The Z86E04 has 1K of OTP ROM and clocked at 8Mhz but the ESR meter only used half of the clock freq. On the E14 site it looks like the replacement chip Z86E08 which has 2K of OTP ROM is cheaper thanthe 1K version, both in 18 pin Dip package.

https://my.element14.com/jsp/search/browse.jsp;jsessionid=ZRBQQQT1W00IKCWNBBSBFTY?N=0&Ntk=gensearch&Ntt=z86e04&Ntx=mode+matchallpartial&exposeLevel2Refinement=true&suggestions=false&ref=globalsearch&_requestid=13699

If I were to do this project, I would use something like 16F1829 which has more memory and more I/O pins and can be programmed in high level language. I believe the author of the ESR was using assembly language in order to squeeze the code into 1K of ROM.

Allen

 

[Kripton2035]

if you want to build this bob parker esr meter and you dont have the chip, then you also need the firmware to put into the chip and as this has not been made public you're in trouble...
here you can find other esr meters you can build yourself, with public open source firmwares, or at least the hex files.
**broken link removed**

 

[Allen6502]

That was really gold mine on ESR meters from Analog to Digital, simple to sophisticated. I'll go through the list of links one by one when I have some free time.

Thanks

Allen

 

[pgr2002]

Thanks. but without firmware the making of the circuit does not fructify and hence I will be making another one and inform.