working a real gauge without PMSys.

[Mike.Powell]

Okay, so for the voltage reading made in parallel with the gauge, the multimeter was set to the 15V scale and the reading is 1.5V

For the current reading made in series with the gauge, the reading was also 1.5? and the multimeter was set to what current scale?

[Jackpilot]

Mike

Bought a nice digital Unitrend multi...mine was really primitive

Here we are

AA Battery alone 1.594V
Parallel reading 1.593V
Series reading 1.02 mA

How's that
Jack

[Matt Olieman]

Hooray Jack.... You did it... Congratulations You graduated from analog to digital.

This seems like a fun project, very curious how it is going end up working. Look forward to seeing the end results Jack.

Matt Olieman

[mauriceb]

Hooray Jack.... You did it... Congratulations You graduated from analog to digital.

And the next logical step is to move up to FS98

Maurice

[Jackpilot]

Mau

One more like that and I switch to Airbus !!!

[mauriceb]

Mau

One more like that and I switch to Airbus !!!

And what would you do with all those nice mechanical gauges in an Airbus?

Maurice

[Mike.Powell]

Mike

Bought a nice digital Unitrend multi...mine was really primitive

Here we are

AA Battery alone 1.594V
Parallel reading 1.593V
Series reading 1.02 mA

How's that
Jack

Looks to me like your gauge is a moving coil style meter likely with an internal resistor to boost the total resistance to roughly 1.5KOhms. Nominal sensitivity is 1 ma full scale.

If you put a standard 3.3KOhm resistor in series with it and connect the resistor to a switched 5 volt source, you should see the gauge swing slightly over full scale. If you put a 1000 microFarad capacitor directly across the gauge, this gives a time constant of about 1 second. (If you use the time constant formula posted earlier, the resistance you use is the parallel combination of the 3.3K series resistor and the 1.5K resistance of the gauge,or about 1K.)

Adjust the value of the 3.3K resistor to change the final deflection of the gauge pointer. I wouldn't go any lower than 3K if you connect to 5 volts. Don't want to toast the gauge.

Adjust the value of the cap to change the time constant. 2000 microFarad will give you 2 seconds, 3000 gives you 3, and so on.

[Jackpilot]

Mike

Confirm this is OK.

[Mike.Powell]

That's it, but one issue with using a pot is it leaves room for turning it to too low a value.

If you are going to connect to 5 volts, I'd feel more comfortable seeing a 3K (or there abouts) resistor in series with the pot. It's just a bit occupational paranoia. Maybe once, possibly twice , I've let the magic smoke out by not being careful enough.

[rottenlungs]

See I knew a big fat capacitor would be there somewhere!

Drifting of topic one of my early memories is of my dad demonstrating what happens when you put +400vdc through a 63v rated electrolytic cap. after a fraction of a second there`s a big bang and a snowstorm of (no doubt highly toxic) dust raining down. Apparently this was the prank of choice at London Underground`s signalling workshops back in the 1960`s! I also had fun as a kid wiring every cap I could find in parallel and using this thing as a makeshift spot-welder!

Ah nostalgia - it just ain`t what it used to be! lol

Looks to me like your gauge is a moving coil style meter likely with an internal resistor to boost the total resistance to roughly 1.5KOhms. Nominal sensitivity is 1 ma full scale.

If you put a standard 3.3KOhm resistor in series with it and connect the resistor to a switched 5 volt source, you should see the gauge swing slightly over full scale. If you put a 1000 microFarad capacitor directly across the gauge, this gives a time constant of about 1 second. (If you use the time constant formula posted earlier, the resistance you use is the parallel combination of the 3.3K series resistor and the 1.5K resistance of the gauge,or about 1K.)

Adjust the value of the 3.3K resistor to change the final deflection of the gauge pointer. I wouldn't go any lower than 3K if you connect to 5 volts. Don't want to toast the gauge.

Adjust the value of the cap to change the time constant. 2000 microFarad will give you 2 seconds, 3000 gives you 3, and so on.