Snip ..
Please clarify the suffix, of the values, of these resistors. I could guess, but that is dangerous. Such as R19 is a 51R resistor…
R1 100
R2 0.1
R20 100
R21 0.1
R23 3300
R4 3300
R5 0.1
R9 2.2
I believe that the difference I noted, between Lt1013/14 models was this...
LT1013CDR Other Models
Temp Max 70*C 125*C
Temp Min 0*C -55*C
Input V Offset 0.3mV 0.8mV
Given that either operational temperature range is acceptable, I take it that the lesser 0.3mV input voltage offset, of the LT1013CDR, would be preferable to the typical 0.8mV, of the other models. Correct?
How important would the better input voltage offset advantage be, in a cost/benefit analysis? LT1013CDR/Dual @ $1.91/unit needs more PCB real estate. LT1014/Quad @ $5.02; YMMV by footprint. For me, at 5 MOSFETS, 4 x $1.91 < $2 x 5.02 and real estate doesn't matter, because 100mm x 100mm is a flat price.
There are some industry standard pinouts for dual and quad op-amps.
These pinouts are widely used and there are many parts that will fit a board designed with these pinouts.
The LT1013 uses a non-standard footprint:
This is not really a good choice, because it means you can't try other op-amps.
The LT1014 use a modified footprint:
There are two extra pins, no connect (nc) pins, but this causes the numbering to change. If you use this footprint, the LT1014 can be used and other parts with the standard footprint will also work.
The full scale voltage on the shunt resistor is 250mV so at 10% of full scale, 25mV, a 0.3mV offset is a little over 1% error. This give you an idea of the sensitivity to the offset voltage Vos.
Resistor values given without m (milli), k (kilo) or M (Meg) are in Ohms, no suffix.
So, is it okay to release the KiCad File?
Hi,
I am going to share the design and construction of an ESR Meter adapter design and construction. The plan is to end up with a design that is similar in appearance to Dave's ucurrent that will allow a DMM to be used as an ESR meter.At this point in time I have not built the circuit.
The requirements are:
Snip ...
Jay_Diddy_B
I know that the shunt resistors need to be 1%, IIRC. Are there any other special components requirements? High wattage resistors, etc... Thanks
I have released schematic in the past, that I haven't built but I have marked them as such.
It would be courteous to reference this thread on a schematics and board artworks that you release.
I have released schematic in the past, that I haven't built but I have marked them as such.This is what I have/am intended to do. I just would have more confidence, in my work, if there was a consensus that it is correct. Not as to design operations, but as to circuit completeness and correctness. My desire is to contribute to the DIY community, by helping with creating a KiCad file, which should have wide utility. I don't feel any obligation, to warrant the design... nor should you, given open source nature, of this thread.It would be courteous to reference this thread on a schematics and board artworks that you release.Yes, I have remembered to do that. The schematic already has your name/handle credit. I will add the link info. My board layout already has both, but I really hadn't intended to release it, because it is tweaked, to my purposes. But, if someone wants it, I would share it, readily...
There is one important connection missing, between D1 cathode and V1 input.
On the double supply version, the scaling factor is wrong. You have 8 x 0.2 resistors in parallel so the scaling is 25mV / A:
Here are some comments on the input connector: The schematic shows the part as conn_0.1x2, which suggest this type of connector: The current rating of the connector is determined by the size of the wire you can attach to the mating part. This is limited to 22 awg (0.32 mm2) which is about 1A. I would use something else.
T1d,
You need to sort out the op-amp pin numbers.
In an earlier message you had decided to use the LT1013 op-amp with the non-standard pin connections:
But you are showing the, standard pinout, quad op-amp on the schematic:
Regards,
Jay_Diddy_B
T1d,
You need to sort out the op-amp pin numbers.
In an earlier message you had decided to use the LT1013 op-amp with the non-standard pin connections:
But you are showing the, standard pinout, quad op-amp on the schematic:
Regards,
Jay_Diddy_B
This is the correction, to the Single Supply model. The reference numbers will be R5 and R6.
Another minor error - the 100R resistor for the monitor output (near R21 labelled R?) connects to ground instead of the junction of R21 and M2 source pin.