Hello Fred, Regarding your question on Keithley SourceMeters: Short question, keithley makes source meters, They are in the micromeasurements handbook but I can not really place this. It sounds like a sort of IV meter, or coulomb meter but for DC. Not planning to buy one, just curious. They are basically precision power supplies with precision measurement capabilities. They are frequently used to test VCSELs (a type of laser diode) and LEDs. Here is part of the description from <http://www.keithley.com/products/dcac/currentvoltage/gpmp?mn=2400>: All SourceMeter models provide precision voltage and current sourcing as well as measurement capabilities. Each SourceMeter instrument is both a highly stable DC power source and a true instrument-grade 6½-digit multimeter. Brent

At a quick glance, the Keithley box looks like an HP 4140 or an earlier PAR C-V plotter. These things characterize PN junctions by integrating the current for a series of voltage steps. The integral of the current.dt is the charge, so they can work back and figure the capacitance. They effectively measure the capacitance of the SCL as a function of voltage. Of course the SCL is a function of the reverse bias on t6he junction. -John ================== > Hello Fred, > > Regarding your question on Keithley SourceMeters: > > Short question, keithley makes source meters, They are in the > micromeasurements handbook but I can not really place this. It sounds like > a sort of IV meter, or coulomb meter but for DC. Not planning to buy one, > just curious. > > > They are basically precision power supplies with precision measurement > capabilities. They are frequently used to test VCSELs (a type of laser > diode) and LEDs. > > Here is part of the description from > <http://www.keithley.com/products/dcac/currentvoltage/gpmp?mn=2400>: > > All SourceMeter models provide precision voltage and current sourcing as > well as measurement capabilities. Each SourceMeter instrument is both a > highly stable DC power source and a true instrument-grade 6½-digit > multimeter. > > Brent > > > > _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. > >

Hi John: A SourceMeter is just the combination of a Voltage/Current source and a meter that can measure current/voltage. More like the HP 4141 or 4142 than the 4140. The tricky part of using them to measure semiconductors is setting the compliance for the sources so that you don't blow out the semi. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/Clarke4Congress.html J. Forster wrote: > At a quick glance, the Keithley box looks like an HP 4140 or an earlier > PAR C-V plotter. > > These things characterize PN junctions by integrating the current for a > series of voltage steps. The integral of the current.dt is the charge, so > they can work back and figure the capacitance. They effectively measure > the capacitance of the SCL as a function of voltage. Of course the SCL is > a function of the reverse bias on t6he junction. > > -John > > ================== > > >> Hello Fred, >> >> Regarding your question on Keithley SourceMeters: >> >> Short question, keithley makes source meters, They are in the >> micromeasurements handbook but I can not really place this. It sounds like >> a sort of IV meter, or coulomb meter but for DC. Not planning to buy one, >> just curious. >> >> >> They are basically precision power supplies with precision measurement >> capabilities. They are frequently used to test VCSELs (a type of laser >> diode) and LEDs. >> >> Here is part of the description from >> <http://www.keithley.com/products/dcac/currentvoltage/gpmp?mn=2400>: >> >> All SourceMeter models provide precision voltage and current sourcing as >> well as measurement capabilities. Each SourceMeter instrument is both a >> highly stable DC power source and a true instrument-grade 6½-digit >> multimeter. >> >> Brent >> >> >> >> _______________________________________________ >> volt-nuts mailing list -- volt-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts >> and follow the instructions there. >> >> > > > _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. > > >