Hi Everyone, I thought I would post a bit about power supplies. Something as simple as trying to measure ripple on the output can be very inaccurate, overstating ripple amplitude by a lot, 100% over stated is not all that unusual.
One problem arises from common mode noise on the output that gets into the structure of the probe used for the measurement. Most probes have modes resulting in display of voltages that are not actually present. If you doubt this, just connect both terminals of a scope probe to the low end, say ground, of a power supply output and you will often see a significant signal that is not actually there. Whatever one measures with a shorted probe on the ground side of the supply output is the error in the measurement and can easily exceed the actual ripple voltage present on the output. Have you seen this? I cover this in detail in my presentations. Doug [https://lh4.googleusercontent.com/_HuR3Ky2TF_XhFHyxnYRmiq7nHQldnMsPNYFaLG6kb5T4y8MeCe-BDC_BscJtSFgszSSjssihHS-pjM3-jwNP8S0CwE-gN8fsRsPkojiAlmpBwb20vIVizS-siCUywW_jqrefbVr] - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to [email protected] All emc-pstc postings are archived and searchable on the web at: https://www.mail-archive.com/[email protected]/ Website: https://ewh.ieee.org/soc/pses/ Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to unsubscribe) List rules: https://ewh.ieee.org/soc/pses/listrules.html For help, send mail to the list administrators: Mike Sherman at: [email protected] Rick Linford at: [email protected] For policy questions, send mail to: Jim Bacher: <[email protected]> _________________________________________________ To unsubscribe from the EMC-PSTC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1
