John Larkin wrote>I tend to not trust L or C meters, especially cheap ones. I connect a >50 ohm sine wave generator to a cap or inductor and spin the knob and >watch the frequency response, which tells me a lot in a few seconds.My very cheap LC meter simply is a frequency meter that uses a reference C for L measurement and a reference L for C measurement, the counter is xtal based. Although my reference L is just junk box inductors, the reference C is quite precise. Nothing wrong with that. And for measuring changes the absolute value is not so important anyways. http://panteltje.com/panteltje/pic/lc_pic/ Why spend more on a box that is probably worse and cannot be modified.
X5R vs X7R MLCC
Started by ●November 14, 2018
Reply by ●November 17, 20182018-11-17
Reply by ●November 17, 20182018-11-17
On Wed, 14 Nov 2018 15:49:33 -0800 (PST), gnuarm.deletethisbit@gmail.com wrote:>I use a 1210 X5R 25V 10% MLCC for input DC blocking. Supply is drying up and I want to place an order to support production for a while. In performing a Digikey/Mouser search I see there are now X7R devices in the same footprint. I know the X7R will be more stable under DC voltage which is an advantage *if* there is much DC on the input. The amplifier circuit has a 6 volt DC bias on the input (half way to the +12 volt rail). The caps prevent the input from seeing this bias. The design passes all functional tests in production (including frequency response) with the X5R devices. > >I'm thinking of making the X7R an alternate device going forward. There are only four devices on the board, so a small increase in price is not so significant. I'm just wondering if there is any technical downside to using the X7R formulation in place of the X5R. Or is the X7R formulation all upside relative to the X5R?Temperature. We can't use X5R because they're only good to 85C.
Reply by ●November 17, 20182018-11-17
On Wed, 14 Nov 2018 15:49:33 -0800 (PST), gnuarm.deletethisbit@gmail.com wrote:>I use a 1210 X5R 25V 10% MLCC for input DC blocking. Supply is drying up and I want to place an order to support production for a while. In performing a Digikey/Mouser search I see there are now X7R devices in the same footprint. I know the X7R will be more stable under DC voltage which is an advantage *if* there is much DC on the input. The amplifier circuit has a 6 volt DC bias on the input (half way to the +12 volt rail). The caps prevent the input from seeing this bias. The design passes all functional tests in production (including frequency response) with the X5R devices. > >I'm thinking of making the X7R an alternate device going forward. There are only four devices on the board, so a small increase in price is not so significant. I'm just wondering if there is any technical downside to using the X7R formulation in place of the X5R. Or is the X7R formulation all upside relative to the X5R? > > Rick C. > > Tesla referral code -- https://ts.la/richard11209Has someone tested the 10uF caps. 0.47 and 0.1 can be substituted with polyester or something but 10uF is harder to replace without electrolytics.
Reply by ●November 17, 20182018-11-17
On Sat, 17 Nov 2018 08:32:34 GMT, <698839253X6D445TD@nospam.org> wrote:>John Larkin wrote >>I tend to not trust L or C meters, especially cheap ones. I connect a >>50 ohm sine wave generator to a cap or inductor and spin the knob and >>watch the frequency response, which tells me a lot in a few seconds. > >My very cheap LC meter simply is a frequency meter >that uses a reference C for L measurement >and a reference L for C measurement, >the counter is xtal based.My AADE meter works like that. It's great for small caps and small inductors, terrible for large values. Last week I measured the inductance of a winding on a biggish toroid. The AADE read low by about a factor of 4. -- John Larkin Highland Technology, Inc lunatic fringe electronics
Reply by ●November 17, 20182018-11-17
On Saturday, 17 November 2018 23:57:08 UTC, LM wrote:> On Wed, 14 Nov 2018 15:49:33 -0800 (PST), > gnuarm.deletethisbit@gmail.com wrote: > > >I use a 1210 X5R 25V 10% MLCC for input DC blocking. Supply is drying up and I want to place an order to support production for a while. In performing a Digikey/Mouser search I see there are now X7R devices in the same footprint. I know the X7R will be more stable under DC voltage which is an advantage *if* there is much DC on the input. The amplifier circuit has a 6 volt DC bias on the input (half way to the +12 volt rail). The caps prevent the input from seeing this bias. The design passes all functional tests in production (including frequency response) with the X5R devices. > > > >I'm thinking of making the X7R an alternate device going forward. There are only four devices on the board, so a small increase in price is not so significant. I'm just wondering if there is any technical downside to using the X7R formulation in place of the X5R. Or is the X7R formulation all upside relative to the X5R? > > > > Rick C. > > > > Tesla referral code -- https://ts.la/richard11209 > Has someone tested the 10uF caps. 0.47 and 0.1 can be substituted with > polyester or something but 10uF is harder to replace without > electrolytics.make good use of your pcb planes :) Yes, the smiley indicates a joke for anyone not functional enough to realise that. Most boards can also tolerate a drop in quantity of dewhatsitting. Decoupling caps. NT
Reply by ●November 18, 20182018-11-18
John Larkin wrote>On Sat, 17 Nov 2018 08:32:34 GMT, <698839253X6D445TD@nospam.org> >wrote: > >>John Larkin wrote >>>I tend to not trust L or C meters, especially cheap ones. I connect a >>>50 ohm sine wave generator to a cap or inductor and spin the knob and >>>watch the frequency response, which tells me a lot in a few seconds. >> >>My very cheap LC meter simply is a frequency meter >>that uses a reference C for L measurement >>and a reference L for C measurement, >>the counter is xtal based. > >My AADE meter works like that. It's great for small caps and small >inductors, terrible for large values. > >Last week I measured the inductance of a winding on a biggish toroid. >The AADE read low by about a factor of 4.Indeed, best for small inductors like for RF. Usually I just calculate toroids from number of turns and core material Seems to work so far, and measure temperature.... scope it.. http://panteltje.com/pub/h501s_drone_remote_power_lab_test_IMG_6271.JPG About 70 W, 100 kHz, some RF stuff on the wave form... transformed up, then down again, rectified, then a car headlight as load. See that fan? My latest invention, old computah fan, blowing away from where I am soldering, creates a low pressure behind the soldering area, so no more solder smoke in my nose, smoke flows away from you.
Reply by ●November 18, 20182018-11-18
On 18/11/18 2:11 pm, John Larkin wrote:> On Sat, 17 Nov 2018 08:32:34 GMT, <698839253X6D445TD@nospam.org> > wrote: > >> John Larkin wrote >>> I tend to not trust L or C meters, especially cheap ones. I connect a >>> 50 ohm sine wave generator to a cap or inductor and spin the knob and >>> watch the frequency response, which tells me a lot in a few seconds. >> >> My very cheap LC meter simply is a frequency meter >> that uses a reference C for L measurement >> and a reference L for C measurement, >> the counter is xtal based. > > My AADE meter works like that. It's great for small caps and small > inductors, terrible for large values.I think it uses a relay to switch in and out an extra capacitor, which allows it to calibrate out most of the tolerances.> Last week I measured the inductance of a winding on a biggish toroid. > The AADE read low by about a factor of 4.At what frequency? These meters use an oscillator that varies over a very wide spread, and they don't tell you what the actual test frequency was. My guess: it was accurate, but not at the frequency your other gear measured it at. Or it was affected by the additional capacitance of the toroid. Clifford Heath.
Reply by ●November 18, 20182018-11-18
PS I have used my LC meter to get the Al of toroids from a given number of turns, seems to work OK. Lots of unknown cores from old computah power supplies etc.
Reply by ●November 18, 20182018-11-18
On 11/17/18 10:11 PM, John Larkin wrote:> On Sat, 17 Nov 2018 08:32:34 GMT, <698839253X6D445TD@nospam.org> > wrote: > >> John Larkin wrote >>> I tend to not trust L or C meters, especially cheap ones. I connect a >>> 50 ohm sine wave generator to a cap or inductor and spin the knob and >>> watch the frequency response, which tells me a lot in a few seconds. >> >> My very cheap LC meter simply is a frequency meter >> that uses a reference C for L measurement >> and a reference L for C measurement, >> the counter is xtal based. > > My AADE meter works like that. It's great for small caps and small > inductors, terrible for large values.Well, it's just a poor little LM311 inside. ;)> > Last week I measured the inductance of a winding on a biggish toroid. > The AADE read low by about a factor of 4.Blech. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Reply by ●November 18, 20182018-11-18
Phil Hobbs>On 11/17/18 10:11 PM, John Larkin wrote: >> On Sat, 17 Nov 2018 08:32:34 GMT, <698839253X6D445TD@nospam.org> >> wrote: >> >>> John Larkin wrote >>>> I tend to not trust L or C meters, especially cheap ones. I connect a >>>> 50 ohm sine wave generator to a cap or inductor and spin the knob and >>>> watch the frequency response, which tells me a lot in a few seconds. >>> >>> My very cheap LC meter simply is a frequency meter >>> that uses a reference C for L measurement >>> and a reference L for C measurement, >>> the counter is xtal based. >> >> My AADE meter works like that. It's great for small caps and small >> inductors, terrible for large values. > >Well, it's just a poor little LM311 inside. ;)If that is so, then it is quite a different thing from what I was referring to as 'My very cheap LC meter', scroll down here for accuracy and description: http://panteltje.com/panteltje/pic/lc_pic/
