AdapterGuru
Know before you plug in
INSTANT POLARITY SAFETY EVALUATOR

DC Polarity Checker & Symbol Decrypter

Connecting a reversed polarity adapter will destroy electronic circuitry in less than a second. Match the laser-printed polarity symbols on your device and adapter before plugging in.

⚡ Common Device Presets:

1. Target Device Socket

What the gadget expects
Device Required Schematic
Device requires: Center Pin = Positive (+), Outer Barrel = Ground (-)

2. Power Adapter Brick

What the adapter delivers
Adapter Output Schematic
Adapter outputs: Center Pin = Positive (+), Outer Barrel = Ground (-)

Polarity Matches: SAFE TO CONNECT

MATCH ⊕ = ⊕

Both the device and adapter share the exact same polarity configuration. Current will flow safely into internal power regulators.

🔍How to Read the Polarity Symbol on Your Power Brick

Center Positive ⊕ (Most Common)

The line originating from the Plus (+) sign points directly to the center solid dot inside the C-ring. The Minus (-) sign connects to the outer C-ring (barrel sleeve).

Used on: Wi-Fi Routers, CCTV, Laptops, LED Strips, Desktop Monitors.
Center Negative ⊖ (Music & Audio)

The line originating from the Minus (-) sign points directly to the center solid dot. The Plus (+) sign connects to the outer C-ring.

Used on: Boss Guitar Pedals, Audio synthesizers, Vintage Keyboards.

⚡How to Verify Polarity with a Digital Multimeter

Step 1: Set to DC Voltage

Turn the multimeter dial to DC Volts (⎓ V or VDC) at 20V range. Plug the power adapter into wall AC power.

Step 2: Probe Contacts

Touch the RED probe inside the hollow center pin and the BLACK probe against the outside metal barrel.

Step 3: Read Sign

If the screen shows +12.0V (positive), it is Center Positive. If it shows -12.0V (minus sign), it is Center Negative.

Need to invert polarity for guitar pedals?

If your adapter is Center-Positive and your pedal requires Center-Negative, you can use an inexpensive DC Polarity Reversing Adapter Cable instead of buying a new power supply.

Full 6-Point Checker
Interactive Suite

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