High voltage detection counter

V

vortex0606

New Member
Hi I'm looking for a simple circuit that would be inexpensive that could detect every time a high voltage is present. The voltage could be upwards to 2000 volts very low amperage. Looking for a way to detect every time this voltage is present by a user turning the switch on. So some kind of counter. Any help would be appreciated
 
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DO you want to count the number of times HV starts up ? If so
what do you want to do with the results, display on LCD or USBUART
or ?

Also how does count get reset ?


Regards, Dana.
 
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All counters must be defined by some AC or DC trigger threshold that you must define in addition to your Vmax. Also the noise must be defined in amplitude variations to have hysteresis to prevent false counts near the threshold.. Logic levels must be defined for the counter such as 5V or 3.3V etc. based on your preference.
Then the display of the count or user interface must be defined. All I/O's user interfaces must be defined including reset.

Once upon a time I used the 1st SEARs LED calculator as a counter using a CMOS analog switch across the "=" key after 1 + was initialized.
 
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What is the threshold voltage for determining what is and is not a "high voltage" event?

Also, what power sources are available to power the timer circuit and display?

Do you want to build everything from scratch, or use a counter module from ebay?

What is the max count?

ak
 
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Thanks for the comments I appreciate it. I'd like to build it from scratch if possible. The voltage threshold is between 2,000 and 3,000 volts AC. The voltage will be zero when not in use. Any type of voltage detection I would be happy with logging as an event. Power source would be two double A batteries. The results of the counter I'd like displayed on a small LED for now. Maybe something Bluetooth later on but I want to start basic.
 
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Can you program micros ?

A V divider made from HV resistors (axial long body) or HV capacitors would
easily translate the AC to logic level, use diode/zener clamps to insure input
to processor stays within spec. Using sampling with processor validate input
is line frequency one way, or rectify and detect dc level another (although this
adds significant latency due to C filter needed on rectifier output).

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Display could be OLED. Could consider using Tuniot on ESP32 module with
OLED display to get count on web. Example of what it takes to create server/
client interface to WiFI, this is block programming code. Tuniot converts your
block config to Arduino Code, and uses Arduino programmer utility to program
module. So you could have local count on module display as well as net interface
using IOT type server for interface to user, eg. phone or PC.....

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Use the interrupt block in Tuniot to detect presence of AC on pin, to increment a counter on
first detection, and then idle until AC disappears (essentially resetting detection loop) .....

Tutorials :
Another example : https://www.edaboard.com/threads/verizon-remote-hotspot-controller.400349/


Regards, Dana.
 
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Thanks for all the info definitely some things I need to consider. Not sure if it's out of my ability. Would you have a rough idea of a schematic would help me understand it better.
 
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Thanks for the info !!Definitely what I'm looking for down the road is to get it on a server. But for right now I definitely would just want to display on an OLED.
 
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Not what you want but, just for ideas.
I am using a 22nF 3000V capacitor to divide down the HV AC down to something that will light a LED.
22nF=20mA in the LED, 10nF=10mA, 4.7nF=5mA (at 2kv rms 60hz)
The LED will reduce brightness with reduced voltage. So 1kv= half current.
I have a simpler version of this if you want less parts.
R1,2,C1 are special and not just any part.

ps
It works just fine with C2 removed. I have a version of the LED that allows D1,2,3,5 to be removed.
 
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Thanks for the schematic it's definitely a good start for me better than where I was with no ideas. I could always work on replacing the LED indicator with some kind of counter.
 
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Another idea.
I am using a TLP182 opto isolator to keep the HV away from people. Note the schematic shows a DC isolator but use an AC isolator. D1 and U1 are one part using the TLP182 or any AC isolator. The isolator will hold off 3kv if thinks go to hell or someone reverses the input leads.

A AC isolator has two LEDs in it so it does not care which way current flows.
 
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A have a few questions.
  • What is the typical voltage when it's not 'high'?
  • What is the typical rise time (slew rate) of the voltage source?
  • What is the impedance of the voltage source?
  • Can it stutter on it's way to the high voltage level? (think switch bounce)
    • If so, what is the typical timing of those spurious pulses?
    • Do you want to count each of those pulses, or just one for the general event?
 
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Yeah I like that idea Definitely makes it safer I didn't think about that Thanks for the idea
 
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Hi The typical voltage when not high is 0. I think the The rise time would be like 300 to 500 milliseconds. Pretty constant when it climbs up to that voltage. I just want to count the one time event then when it goes back to zero count the next event.
 
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