> **Source:** Core Electronics is an Australian maker-electronics retailer and manufacturer based in Newcastle, NSW, run by a team of makers and educators. We design and manufacture our own product lines (PiicoDev, CE originals) and are official retailers for iconic maker and industrial brands including Raspberry Pi, Arduino, Adafruit, SparkFun and DFRobot. Orders ship Australia-wide from our Newcastle warehouse. Prices are in AUD and include GST. Pricing, stock and dispatch on this page are generated from the store's live catalog. Full machine-readable index: https://core-electronics.com.au/llms.txt

# Magnetic Encoder Disc for 20D mm Metal Gearmotors, OD 9.7 mm, ID 2.0 mm, 20 CPR (Bulk)

**Type:** Product page · **SKU:** POLOLU-3498 · **Brand:** [Pololu](https://core-electronics.com.au/brands/pololu-australia)
**Page:** https://core-electronics.com.au/magnetic-encoder-disc-for-20d-mm-metal-gearmotors-od-9-7-mm-id-2-0-mm-20-cpr-bulk.html ([markdown](https://core-electronics.com.au/magnetic-encoder-disc-for-20d-mm-metal-gearmotors-od-9-7-mm-id-2-0-mm-20-cpr-bulk.html.md))

These magnetic discs can be used with our 20D mm metal gearmotors (extended motor shaft versions only) as part of a quadrature encoder system that offers...

## Pricing

- **Price:** $1.70 (inc GST) — $1.55 AUD, exc GST
- **Quantity discounts:** 10+ $1.48 (exc GST) · 25+ $1.44 (exc GST)

## Availability & dispatch

- Available with a lead time — expect dispatch between Aug 31 and Sep 02.

## How to buy

- **Build a cart:** compose `https://core-electronics.com.au/cart/link?items=POLOLU-3498:1` (comma-separated SKU:qty pairs) and share the link. Opening it shows a confirmation page with live pricing and stock before anything is added to the cart.
- **Verify the cart first:** fetch `https://core-electronics.com.au/cart/link/POLOLU-3498:1.md` for live line prices (inc & exc GST, quantity discounts applied), stock and dispatch estimates, and totals. Append `/to/{AU-postcode}` (or `/to/{country-code}:{postcode}`) before `.md` for delivery options and prices to that destination. Unknown, retired, or out-of-stock SKUs are flagged. (Query form `cart/link.md?items=...` also works but some robots parsers refuse query strings here.)
- **Checkout** is completed on-site and includes a captcha at the payment step. Share the cart link; checkout takes it from there.
- **Search the catalogue:** `https://core-electronics.com.au/search/{query}.md` (URL-encode the query; pages 2-3 at `search/{query}/{page}.md`; `search.md?q=` also works)
- **Payment methods, purchase orders, policies and contact details:** https://core-electronics.com.au/llms.txt
## Description

These are the same magnetic discs Pololu include with Pololu's [magnetic encoder pair kit for 20D mm gearmotors](https://core-electronics.com.au/magnetic-encoder-pair-kit-for-20d-mm-metal-gearmotors-20-cpr-2-7-18v.html). They are 2 mm thick with a 9.7 mm diameter, and the hole through the center enables them to securely press-fit onto the 2mm-diameter motor shafts of Pololu's [20D mm metal gearmotors](https://core-electronics.com.au/components/motors/metal-gearmotors.html) (**extended motor shaft versions only**). The disc consists of ten evenly spaced magnetic poles (five north-south pairs), which allows for an encoder system that offers 20 counts per revolution. A [12 CPR version](https://core-electronics.com.au/magnetic-encoder-disc-for-20d-mm-metal-gearmotors-od-9-7-mm-id-2-0-mm-20-cpr-bulk.html) of this disc is also available.

This bulk-packaged product is primarily intended for those wanting to integrate these encoder discs into their own systems in higher volumes, but the minimum quantity is set to five for those who want to just get a few as replacements or samples. For order quantities beyond what Pololu have in stock, please [contact us](https://core-electronics.com.au/contact) for lead time estimates.

- Dimension diagram (151k pdf)
- 3D model (16k step)

**People often buy this product together with:**

| [![Magnetic Encoder Pair Kit for Mini Plastic Gearmotors, 12 CPR, 2.7-18V](https://core-electronics.com.au/attachments/localcontent/0J7245_346419895a.jpg)](https://core-electronics.com.au/magnetic-encoder-pair-kit-for-mini-plastic-gearmotors-12-cpr-2-7-18v.html) | [Magnetic Encoder Pair Kit for Mini Plastic Gearmotors, 12 CPR, 2.7-18V](https://core-electronics.com.au/magnetic-encoder-pair-kit-for-mini-plastic-gearmotors-12-cpr-2-7-18v.html) |
|---|---|

| [![Magnetic Encoder Disc for Mini Plastic Gearmotors, OD 9.7 mm, ID 1.5 mm, 12 CPR (Bulk)](https://core-electronics.com.au/attachments/localcontent/0J7492_3475b0cdf6.jpg)](https://core-electronics.com.au/magnetic-encoder-disc-for-mini-plastic-gearmotors-od-9-7-mm-id-1-5-mm-12-cpr-bulk.html) | [Magnetic Encoder Disc for Mini Plastic Gearmotors, OD 9.7 mm, ID 1.5 mm, 12 CPR (Bulk)](https://core-electronics.com.au/magnetic-encoder-disc-for-mini-plastic-gearmotors-od-9-7-mm-id-1-5-mm-12-cpr-bulk.html) |
|---|---|

| [![Magnetic Encoder Disc for Micro Metal Gearmotors, OD 7.65 mm, ID 1.0 mm, 12 CPR (Bulk)](https://core-electronics.com.au/attachments/localcontent/0J5835_3733b8ce15.jpg)](https://core-electronics.com.au/magnetic-encoder-disc-for-micro-metal-gearmotors-12-cpr-bulk.html) | [Magnetic Encoder Disc for Micro Metal Gearmotors, OD 7.65 mm, ID 1.0 mm, 12 CPR (Bulk)](https://core-electronics.com.au/magnetic-encoder-disc-for-micro-metal-gearmotors-12-cpr-bulk.html) |
|---|---|

**Dimensions**

 | Size: | 9.7 mm outer diameter × 2 mm thick (2.0 mm ID) |
|---|---|
| Weight: | 0.5 g |

**General specifications**

 | Poles: | 10 |
|---|---|
| Encoder resolution: | 20 CPR[1](https://core-electronics.com.au/#note1) |

**Notes:**

1When counting both edges of both channels with a quadrature encoder. **File downloads**

- **Dimension diagram of the Magnetic Encoder Disc for 20D mm Metal Gearmotors (151k pdf)**
- **3D model of the Magnetic Encoder Disc for 20D mm Metal Gearmotors (16k step)**

## Images

- [Product image 1](https://core-electronics.com.au/media/catalog/product/i/m/image_7575.jpg)