Plectonic

This is approximately 97% true. Some adapters are just plain weird.

Q: WHAT ARE THE MOST COMMON ERRORS?

● Choosing an AC-AC adapter when an AC-DC adapter is required. About 90% of adapters are AC-DC. 

● Choosing an AC-DC adapter with tip negative polarity when positive polarity is required. About 90% of AC-DC adapters are tip positive.

● Not reading the description or title. A search for “AD-0930” will return “AD-0930M” among results. 

● Buying an adapter because its color matches the Sharper Image "Suck Buddy" Baby Thumb Warmer.  Adapters are not color coded.

Q: WHAT ARE mA, A, W, V, VA?

Milliamp = mA

Amp = A

Watt = W

Volt = V

Volt-amp = VA (if you see this unit, ask me for more info)

Conversion: 1000mA = 1A

Q: WHAT DOES AC-DC MEAN? WHAT DOES AC-AC MEAN?

The first two letters are what’s coming into the adapter from the wall.  It doesn’t matter unless you plan to travel (see below). The second two letters are output. It’s what’s going from the adapter into the device, and it definitely matters. Wall adapters can be AC-DC (about 90%), or AC-AC (about 10%). 

Q: DOES INPUT MATTER?

Input is what’s coming from the wall. Everything I sell is suitable for use in North America. If you plan to travel, buy an adapter with an input range that covers both 120 VAC and 240 VAC. The rest of this page focuses on adapter output.

Q: HOW DO I KNOW IF I NEED AN AC-AC ADAPTER OR AN AC-DC ADAPTER?

The type of output current coming out of the adapter can be either AC or DC. Using the wrong one will ruin the machine. About 90% of adapters have DC output. Output voltage often reads quite high on a multimeter. This is normal. I can provide a reference.

Identifying DC Output: An adapter should clearly say output is DC. There are other indications too. If the machine or adapter has a symbol with plus and minus signs, you need DC. If the device may be powered by batteries, you need DC. If you see something like an equal sign (e.g.12V = 500mA), you need DC. If you need AC-DC, you also need to get the right polarity. See below.

Identifying AC Output: An adapter should clearly indicate output is AC. The tilde is also symbol for AC (e.g. 12V ~ 500mA) and can often be found on an adapter or on the machine near the power jack.

Q: WHAT IS POLARITY? (AC-DC ONLY)

If you need an AC-DC adapter with a metal tip, you need to choose the correct polarity. About 90% of barrel tip AC-DC adapters have tip positive (a.k.a. inner positive, center positive) polarity. Almost every phono tip adapter has tip positive polarity. The polarity is often on the adapter and/or designated by a symbol near the power port.  

The left to right order of plus and minus signs is not important! Polarity is indicated by the sign leading to the solid dot in the middle.

Tip Positive:

⊖——(●——⊕

Tip Negative:

⊖——●)——⊕

Q: WHAT IF I DON’T KNOW THE REQUIRED VOLTAGE?

It might be printed near the power jack on the device. If it can regular old batteries, it’s easy. Round batteries supply 1.5V each. A 9V battery supplies 9V, obviously. If this doesn’t help, there are manuals on the Internet, user-submitted images on product review sites, etc. Try googling the model and “filetype:pdf” to find manuals.

Q: CAN AMPS BE HIGHER ON THE ADAPTER?

The output amperage must meet or exceed the device's requirement. 1A = 1000mA.

Q: WHAT IF I DON’T KNOW THE REQUIRED AMPERAGE?

It might be printed near the power jack. The output amperage must meet or exceed the machine’s requirement. Google the machine model and “filetype:pdf” to find manuals. If that doesn't work, contact me. Please provide as much information as possible in the first message. 

Q: WHAT IF THE ADAPTER INDICATES OUTPUT WATTS BUT NOT AMPS?

Watts is volts times amps.