Property talk:P2436

Documentation

• Start a query
• Properties using this qualifier (statistics)
• Count

voltage
difference in electric potential between two points (indicated in volt)

Represents	voltage (Q25428)
Data type	Quantity
Domain	electrified stuff (note: this should be moved to the property statements)
Allowed units	volt (Q25250)
Example	According to this template: 3000 V DC (as qualifier of Florence–Rome railway (Q1158780)type of electrification (P930)overhead contact line (Q110701)) According to statements in the property: Vorab power line (Q2533447) → 220,000 volt 380,000 volt 25 kV AC railway electrification (Q1412243) → 25,000 volt Arduino/Genuino Zero (Q26225909) → 3.3 volt When possible, data should only be stored as statements
Tracking: usage	Category:Pages using Wikidata property P2436 (Q120542753)
See also	frequency (P2144)
Lists	Most recently created items Items with novalue claims Items with unknown value claims Usage history (total) Usage history (main statement) Chart by item creation date Minimum and maximum Items with highest numeric value Items with lowest numeric value Database reports/Constraint violations/P2436
Proposal discussion	Proposal discussion
Current uses	Total 2,525 Main statement 2,489 98.6% of uses Qualifier 36 1.4% of uses

[create Create a translatable help page (preferably in English) for this property to be included here]

Units: “volt (Q25250)”: value unit must be one of listed. (Help)

Exceptions are possible as rare values may exist. Exceptions can be specified using exception to constraint (P2303).
List of violations of this constraint: Database reports/Constraint violations/P2436#Units

Allowed entity types are Wikibase item (Q29934200): the property may only be used on a certain entity type (Help)

Exceptions are possible as rare values may exist. Exceptions can be specified using exception to constraint (P2303).
List of violations of this constraint: Database reports/Constraint violations/P2436#Entity types

Not qualifier only

There seems to be many uses of this property as main value:

SELECT ?item ?itemLabel ?voltage WHERE {
  SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". }
  OPTIONAL { ?item wdt:P2436 ?voltage. }
}
LIMIT 1000

Try it!

In fact, there are about 600 uses of this property as main value, compared to only about 30 as qualifier:

SELECT DISTINCT ?item ?property ?propertyLabel ?asObject ?asObjectLabel
WHERE
{
  ?prop pq:P2436 ?asObject .
  hint:Query hint:optimizer "None" .	
  ?item ?p ?prop . 
  ?property wikibase:claim ?p .  
  ?property wikibase:statementProperty ?ps .
  ?prop ?ps ?value .      
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en"  }    
}
ORDER BY ASC(?propertyLabel) 
LIMIT 1000

Try it!

So I'm removing the constraint that says this property should only be used as qualifier. Feel free to propose how to migrate the existing uses if you disagree... Deryck Chan (talk) 13:28, 30 June 2018 (UTC)

Removed minimum value constraint

There was a minimum value constraint of 0 V. I removed it because negative voltages (relative to ground (Q6501125)) are routinely used in some areas of electronics, e.g. the -5V rail of an ATX power supply. 73.202.12.249