|Apr 02, 2008, 05:19 PM|
Joined Feb 2008
Bruce Abbot Wattmeter
I start to build wattmeter designed by BRUCE ABBOT and many time discussed in RC GROUPS Forum. I need some helps like that:
1) value of items R8, R17, C6, C7 and type of VR1 (I think is a TL431)
2)Function of trim R13, R14, R1 and pushbotton S1, S2 and S3
3) Any people have component side drawing with reference component corresponding at schematic?
4) All other help it's apreciated.
Regards at all fantastic members of RC GROUPS.
|Apr 04, 2008, 03:45 AM|
R8 = 10 Ohms
C6 = 10nF
C7 = 100nF
VR1 = TL431
R13 = Volts calibration (10 turn pot)
R14 = Amps calibration (10 turn pot)
R1 = LCD contrast adjust
S1 = Hold
S2 = page
S3 = reset (not currently implemented)
IC3 is now an MCP6022 (cheaper and more readily available than AD708)
The board design can be veiwed in Eagle Layout Editor, but I have attached a 300dpi image in case you can't get Eagle working.
I have not yet built the 16F88 version, so I can't say for sure that the circuit diagram, layout or software is correct.
I am considering adding a tacho function, which will probably require an external crystal to get sufficient frequency stability. S3 may then be eliminated (no great loss as I am not using it anyway). I also want to use a 2 line LCD. Hope to get this done soon, but - I've also got a few models to finish etc.
|Apr 04, 2008, 04:14 PM|
Joined Feb 2008
Hello BRUCE, thanks for your answer. I would want to still use your availability one in order to ask you follows:
1) it is neccessary to replace AD708 that I have already bought with the MCP6022 or I can mount the AD708?
2)If you have not still built the version with the PIC 16F88, on the PCB that I have realized with your file for EAGLE_PCB that PIC I must use?
3) I have found some differences between the PCB and the schematic one, in particular I have see on the shematic the invertion of pin 17 with the pin 18 respect to PCB.
Thanks still for your aid, and waiting for a kind replay
(Sorry for my very bad english language)