10-06-2024, 11:28 AM
(This post was last modified: 10-06-2024, 11:39 AM by Mike Watterson.)
The postman came 2 hours early.
The little panel meters had no instructions. Investigation showed the red and black on 3 pin plug are power and yellow is voltage sense, which can't go to 100 as the DP doesn't move. In theory goes to 99.9V.
The current shunt is a SM resistor which needed desolder braid and sharp knife to remove. Then even with a 100K series resistor it showed about 62.0 if any voltage applied. I added a 10K to zero volts.
11V gives about 52.3 on display, which would be about 1V in.
There are two presets to set V and A calibration.
So an opamp (Norton LM3900, though there is a later upgrade (1981) the LM359. doesn't need a transistor current source added on output. I need to make 50 mA on sense resistor in series with HT be about 1V on op-amp out. I will see if the preset allows setting 1V in (without shunt) to be exactly 50.0 on display.
The Voltmeter part measures 311K when off. At 11V on display it takes 34.7 μA, which is 297K. I'll see if a suitable series resistor assuming 300K allows the voltage adjustment to be exactly 10.0 at 100V, so 700V would be 70..0 as the spec claims it measures to 100V (99.9 really). That would be 2.7 M Ohms? Price was £7.77 in. for TWO on Amazon.
I also got some packs of stupidly cheap LED voltmeters. Three packs, each with 4 displays (red, yellow, green and blue). So TWELVE little LED voltmeters for £8.77 total on Amazon. Also no instructions. The PCB has a solder jumper (not always soldered) to connect Vmeasure to +Vsupply. Opening that and adding a wire works. The displays work off 5V and looks like a LDO regulator. There might be instructions here in German.
I searched the link and there is, and you can select English on the site and for the ebooks,
The little voltmeters.
It's a shop, so they want your email!
This might even be the same V & A module (but I didn't buy it from them)
EDIT:
The Download links appear after you complete checkout, so if you are paranoid you can use a fake email, name and physical address and not save it. Obviously real info for physical purchases.
Of course they are PDFs, not ebooks.
The booklets are pointless if you understand electronic as the connections are obvious from examination. That and specification is all that is in it. The spec is nothing extra than the Amazon web pages.
The little panel meters had no instructions. Investigation showed the red and black on 3 pin plug are power and yellow is voltage sense, which can't go to 100 as the DP doesn't move. In theory goes to 99.9V.
The current shunt is a SM resistor which needed desolder braid and sharp knife to remove. Then even with a 100K series resistor it showed about 62.0 if any voltage applied. I added a 10K to zero volts.
11V gives about 52.3 on display, which would be about 1V in.
There are two presets to set V and A calibration.
So an opamp (Norton LM3900, though there is a later upgrade (1981) the LM359. doesn't need a transistor current source added on output. I need to make 50 mA on sense resistor in series with HT be about 1V on op-amp out. I will see if the preset allows setting 1V in (without shunt) to be exactly 50.0 on display.
The Voltmeter part measures 311K when off. At 11V on display it takes 34.7 μA, which is 297K. I'll see if a suitable series resistor assuming 300K allows the voltage adjustment to be exactly 10.0 at 100V, so 700V would be 70..0 as the spec claims it measures to 100V (99.9 really). That would be 2.7 M Ohms? Price was £7.77 in. for TWO on Amazon.
I also got some packs of stupidly cheap LED voltmeters. Three packs, each with 4 displays (red, yellow, green and blue). So TWELVE little LED voltmeters for £8.77 total on Amazon. Also no instructions. The PCB has a solder jumper (not always soldered) to connect Vmeasure to +Vsupply. Opening that and adding a wire works. The displays work off 5V and looks like a LDO regulator. There might be instructions here in German.
I searched the link and there is, and you can select English on the site and for the ebooks,
The little voltmeters.
It's a shop, so they want your email!
This might even be the same V & A module (but I didn't buy it from them)
EDIT:
The Download links appear after you complete checkout, so if you are paranoid you can use a fake email, name and physical address and not save it. Obviously real info for physical purchases.
Of course they are PDFs, not ebooks.
The booklets are pointless if you understand electronic as the connections are obvious from examination. That and specification is all that is in it. The spec is nothing extra than the Amazon web pages.
