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Electrical Power Systems Quality, Third Edition

by Roger C. Dugan

Rated4.4(80 ratings)In stock

Good price

$100.48 is 15% below the $119.20 it normally sells for, and the lowest we've seen in 108 days.

Now
$100.48
Normally
$119.20
Lowest in 108 days
$100.48(Nov 11)
Highest
$141.30
Evidence: Strong108 days tracked12 price changes

Where today's price sits

View on amazon.com (opens in a new tab)

Prices change. Confirm the price on Amazon before you buy. TrackPin may earn a commission if you buy, at no cost to you; it never changes a verdict.

Get an email when the price drops

Good: 5%+ below normal. Great: 20%+ below. One email when it happens, at a price below today's $100.48. No account, no newsletter.

The listing's crossed-out price

Holds up

The listing shows

crossed out: List $141.30 −29%

Against its normal price

−15% vs $119.20

List $141.30 (−29%) holds up: today's price is 15% below normal.

The crossed-out price is the reference shown on the listing. We don't know how it was set; we only compare it with prices we've observed. How we check →

Price history

Tracked since Jul 26 · 108 days · 12 price changes

Loading the price chart.

  • Price
  • Not checked for 3+ days
  • Normal $119.20
  • 5% or more below normal

How often does it drop below normal?

In the 108 days we've tracked it, it stayed 5% or more below today's normal price for an hour or more 5 times, typically lasting about 1 day. It's below normal right now.

A count of what happened, not a prediction.

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Get this as JSONThe same verdict and prices, from the TrackPin API.
GET/api/v1/product/B00743YQ9M
Request
curl https://trackpin.co/api/v1/product/B00743YQ9M \
  -H "x-api-key: $TRACKPIN_API_KEY"

This is exactly what the API returns for this product. Free keys include 100 requests a day.

Request a key
Live response, As of 17:47 UTC
{
  "asin": "B00743YQ9M",
  "title": "Electrical Power Systems Quality, Third Edition",
  "image": "https://m.media-amazon.com/images/I/71QmcJp996L._AC_SL500_.jpg",
  "currency": "USD",
  "category": "eBooks",
  "category_label": "eBooks",
  "in_stock": true,
  "price": {
    "current_cents": 10048,
    "reference_cents": 11920,
    "discount_pct": 15.7,
    "is_deal": true,
    "observed_at": 1794414751871,
    "changed_at": 1794397041957,
    "checked_at": 1794414751871,
    "source": "stored"
  },
  "verdict": {
    "label": "good",
    "text": "Good price",
    "pct_vs_normal": 15.7,
    "evidence": "strong",
    "stale": false,
    "suspect": false,
    "steady_since": null,
    "sentence": "Good price. $100.48 is 15% below the $119.20 it normally sells for, and the lowest we've seen in 108 days."
  },
  "listing_claim": {
    "label": "List:",
    "listing_reference_cents": 14130,
    "claimed_pct": 29,
    "real_pct": 15.7,
    "class": "holds_up",
    "observed_at": 1794397353959
  },
  "stats": {
    "min_cents": 10048,
    "max_cents": 14130,
    "avg_cents": 12037,
    "history_days": 108,
    "price_levels": 37,
    "price_changes": 12,
    "distinct_prices": 5,
    "lowest_at": 1794397041957
  },
  "history": [
    {
      "price_cents": 13499,
      "from": 1791147537004,
      "to": 1791148003567
    },
    {
      "price_cents": 11920,
      "from": 1791499972713,
      "to": 1793777554706
    },
    {
      "price_cents": 10048,
      "from": 1793790734245,
      "to": 1793869620154
    },
    {
      "price_cents": 11920,
      "from": 1793877112430,
      "to": 1794396486867
    },
    {
      "price_cents": 10048,
      "from": 1794397041957,
      "to": 1794414751871
    }
  ],
  "last_seen": 1794414751871
}
// … 32 more steps in the full response

Normal price: the lowest price level the product held for at least 15% of the last 45 days (about a week). Prices within 3% of each other count as one level, and we use the lowest price in that level. How we calculate it → Prices are observations of amazon.com and may be incomplete or delayed. TrackPin is not affiliated with Amazon.