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[email protected]> wrote: A simple on/off LED would quickly deplete a few AA cells which are expected to last months until such time as the LED goes off. >

Why not use a Zener diode (say 10V) in series with a couple of Schottky diodes to drop 10.4V from the 12V line and connect this via a bias resistor to an NPN transistor with a LED and resistor in its

Gentlemen, Thank you for the several, prompt and very helpful suggestions. They are being thoughtfully considered. Regards, Ray, W4BYG -- This email has been checked for viruses by AVG antivirus

Or a : https://www.mpja.com/Battery-Capacity-Indicator-Lead-Acid_LiPO/productinfo/35668+ME/ from Marlin P Jones. I have not used it but have been quite satisfied with the several items I have bought

RV supply places sell a voltmeter with three LEDs for charged, low, flat as in lead acid 6 cells. Probably on aliexpress or ebay or amazon also.

There’s always the off-the-shelf logging solutions with devices that will log upwards of a year or more depending upon sample rates. I use an assortment of loggers of which the more common use is to

A classic circuit uses the LM3914 to give a short bargraph. https://www.nutsvolts.com/magazine/article/led-graph-circuits [email protected]> wrote:

I have a need for a LED indicator to tell if the battery voltage on my RV falls below say 11 volts. Can someone lead me to such a circuit? Just an LED and series resistor will indicate nominal

If you want to get fancy you could have a look at Kevin Darrahs videos on his TrigBoard. believe 1ua. trigBoard Hardware Walkthrough & Tutorial - ESP8266 EXTREME Low Power

That RF harvesting idea is interesting, but unfortunately not applicable in my case. ?I wanted a general purpose dual channel temperature data logger that is completely stand-alone, i.e. does not

The information from Peter and David was instructive. I am working on a data logger which needs to start logging events that occur before a trigger condition to show what event caused the trigger.

[email protected]> wrote: I don’t know what data you are logging, but a friend logs temperature periodically and transmits that data to a recording device. His power source for the data logger is

I have been working on the design of a data logger that will run unattended for several months from three AA cells. I needed a “Battery Low” indicator that would run for a few days on cells

Still active, but I haven't either. Vince. -- Michigan VHF Corporation -- nobucks dot net https://www.nobucksboutique.com http://www.metalworkingfun.com K8ZW - http://www.hamradio.fun

I haven't seen a posting since late February. Is this group still active?

I second Don’s recommendation. My HP4192A has no trouble testing components down to 5Hz with good resolution. It also works well for big Capacitors, too. I needed to measure a 58F (6 series 350F)

What type of capacitor, what working AC and DC voltages, and what sort of application, would require measurement of the complex impedance at 10 Hz? Are you looking for low ESR or low leakage? How

Another good option would be an HP 4192A LF Impedance Analyzer Specifications(Refer to data sheet for complete specifications. )?Frequency Range: 5 Hz to 13 MHz?OSC Level: 5 mV to 1.1 mV?DC Bias: 0

Dr.Kirby, Possible a better method would be to use a low frequency VNA, such as a HPAK - 89410A Vector Signal Analyzer, DC to 10 MHz - - or equivalent. You should be able to extract the vector

Not an LCR meter, but you can improvise this fixture: Generate 10Hz sine, 10V. From this signal, generate 0.1V with exactly 180 degrees phase. Connect the C under test to the 10V. Connect a variable R