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Comment 221 ... 230

date	article	author	comment
11 jun 2016 12:00:02	Arduino wattmeter	Freddy	I don't think I can help you. I avoid the use of libraries. Maybe it has something to do with the differences between row,col addressing used by setCursor() and LCD memory addressing used by the LCD hardware and my software. Was there a reason to use a LCD library?
10 jun 2016 15:13:22	Arduino wattmeter	Jesso	Hello Freddy,I would like to thank you for the time you take to answer my questions. I have a question concerning a different matter. In fact, I'm still working on the project that I've told you about. My question will be about the methods that you use to show results on the screen of the display. Instead of using your methods, I used the Library "LiquidCrystal" in order to replace the method "LcdInitiate" and the method "LcdPrintString" is replaced by the method "Lcd.print". By doing this, I had the same results that I had using your methods. However, when I tried to change the method "LcdWrite" by the method "Lcd.setCursor, I had only the labels of the parameters but I lost their values. What do you advise me to do in this case because I can't really tell what the problem is. Thank you in advance. Best regards, Jesso
10 jun 2016 12:29:01	Arduino wattmeter	Freddy	Kunal, please read the article and the comments here. There are some serious safety issues when using this Wattmeter on mains voltage. And yes, when a suitable voltage divider resistor and shunt is applied the Wattmeter can measure your AC-load. See the article how to calculate these.
10 jun 2016 08:49:47	Arduino wattmeter	kunal	Hello freddy, can this circuit work well with ac load having 230V 20A connected, please help me to construct circuit for ac load power measurement, ac load (AC, light etc.) 230V 20A
01 jun 2016 11:32:13	Fast Lux meter	Freddy	Yes, it looks like the internal input diodes will protect the photodiode against overvoltage. I've never test this but it's worth trying.
01 jun 2016 09:23:47	Fast Lux meter	Manfred	Thanks Freddy. I´m with you. I was thinking of measuring pulsed light (AC-components) in bright surroundings, resulting in a large DC-component. The schematic of the OP37 shows bidirectional protection diodes between the inputs. So the increase of the positive supply up to 20V should not harm the BPW21. Do you agree? I think this would be the optimum to fit all needs. Such a device is missing in my lab. Many thanks for sharing this project with us!
30 mei 2016 23:59:46	Fast Lux meter	Freddy	@Manfred, yes, you can use an asymmetrical supply for the opamp and increase the output voltage swing. But increasing the output swing will worsen your frequency range due to the limiting slew-rate of the opamp.
29 mei 2016 21:53:26	Fast Lux meter	Josh	I don't believe changing the virtual ground should affect the speed of the circuit. I slowed the circuit down by adjusting the value of C1 because I cared more about filtering out noise than taking fast measurements, but that is a separate issue from the extra range gained by dropping the virtual ground a bit lower. You should be able to adjust the voltage divider portion of the circuit without much change to the response time.
29 mei 2016 17:26:58	Fast Lux meter	Manfred	@Josh: Many thanks, but it does not answer my questions. Which means: does the change in supply harm the behaviour of the circuit? I have read all. Slow readings by use of a rail to rail opamp are not special. I am thinking to build Freddys "FAST Lux meter", which is the topic.
29 mei 2016 16:02:05	Fast Lux meter	Josh again	Freddy, I just noticed I neglected to update here, the circuit is working perfectly with the modifications you suggested! \\\\\\\\\\\\\\ \\\\\\\\\\\\\\ Manfred, that depends on your application, see the comments above about the changes Freddy suggested for my application, I switched to a rail to rail of amp and dropped the virtual ground to get a much wider response range.

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