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Discussion of precise voltage measurement

Keithley 2001 Multimeter Fault

Mark Sims

Sun, Mar 7, 2010 4:50 AM

Check the input voltage to the regulator. If it is over 7V then you can use a normal 3 terminal regulator (7805, LM340, etc). The LM1086 has a bit less dropout than these.

I have seen lots of designs where LDO regulators were used when the input voltage was high enough for a regular regulator.

I hadn't realised the LM2940CT-5 was so dependant on the output capacitor
capacitance and ESR for stability until I tested one just now. Can anyone
recommend an upgrade?

Hotmail: Trusted email with Microsoft’s powerful SPAM protection.
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Check the input voltage to the regulator. If it is over 7V then you can use a normal 3 terminal regulator (7805, LM340, etc). The LM1086 has a bit less dropout than these. I have seen lots of designs where LDO regulators were used when the input voltage was high enough for a regular regulator. ------------------------ I hadn't realised the LM2940CT-5 was so dependant on the output capacitor capacitance and ESR for stability until I tested one just now. Can anyone recommend an upgrade? _________________________________________________________________ Hotmail: Trusted email with Microsoft’s powerful SPAM protection. http://clk.atdmt.com/GBL/go/201469226/direct/01/

Alan Scrimgeour

Sun, Mar 7, 2010 8:50 AM

Good idea, thanks, I'll check.

Alan

----- Original Message -----
From: "Mark Sims" holrum@hotmail.com
To: volt-nuts@febo.com
Sent: Sunday, March 07, 2010 4:50 AM
Subject: [volt-nuts] Keithley 2001 Multimeter Fault

Check the input voltage to the regulator. If it is over 7V then you can use
a normal 3 terminal regulator (7805, LM340, etc). The LM1086 has a bit less
dropout than these.

I have seen lots of designs where LDO regulators were used when the input
voltage was high enough for a regular regulator.

I hadn't realised the LM2940CT-5 was so dependant on the output capacitor
capacitance and ESR for stability until I tested one just now. Can anyone
recommend an upgrade?

Hotmail: Trusted email with Microsoft’s powerful SPAM protection.
http://clk.atdmt.com/GBL/go/201469226/direct/01/

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Good idea, thanks, I'll check. Alan ----- Original Message ----- From: "Mark Sims" <holrum@hotmail.com> To: <volt-nuts@febo.com> Sent: Sunday, March 07, 2010 4:50 AM Subject: [volt-nuts] Keithley 2001 Multimeter Fault Check the input voltage to the regulator. If it is over 7V then you can use a normal 3 terminal regulator (7805, LM340, etc). The LM1086 has a bit less dropout than these. I have seen lots of designs where LDO regulators were used when the input voltage was high enough for a regular regulator. ------------------------ I hadn't realised the LM2940CT-5 was so dependant on the output capacitor capacitance and ESR for stability until I tested one just now. Can anyone recommend an upgrade? _________________________________________________________________ Hotmail: Trusted email with Microsoft’s powerful SPAM protection. http://clk.atdmt.com/GBL/go/201469226/direct/01/ _______________________________________________ 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.