0.33 Ω resistor. 1 part is printed R33.
R33 on a chip resistor
0.33 Ω
0.33 Ω resistor
The R stands in for the decimal point, which is how sub-ohm and fractional values are printed.
Check it with a meter
Lift one end and measure across it. A good one reads 0.33 Ω. Measuring it in circuit reads the parallel combination of everything around it, which is almost always lower, never higher: well above 0.33 Ω on the board is a fault. Open, or well above 0.33 Ω, means it has failed: burnt, cracked or corroded. That does not change what to fit: the marking still says 0.33 Ω. A burnt resistor usually means the part it feeds drew too much, so find that before fitting a new one.
On a transistor or diode body (SOT-23, SOT-323), R33 is a part code instead. Those parts are listed below.
The only part printed R33 in this package in our tables
REF3333AIDCK
- What it is
- Voltage reference
- Maker
- Texas Instruments
- Package
- SOT-323
- Pins
- 3
- Details
- 3.9μA, SC70-3, SOT-23-3, and UQFN-8, 30ppm/°C Drift Voltage Reference
- Source
- From the manufacturer's datasheet
Is it dead?
Voltage with the board powered; ohms from each pin to ground with it off.
Working, it reads
Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.
Dead, it reads
- A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
- Supply present, output stuck: failed, or its load has.
- On the board:
- A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
- Compare:
- The surest reference is the same IC on a working board, measured pin by pin.
- Watch for:
- Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
One code, several parts
Marking codes are not unique. In the standard code book, 6H on a SOT-23 is an NPN transistor, a varicap, an N-channel JFET, two digital transistors, a 3.6 V voltage detector: six parts from five makers. So a search shows the parts we hold under that code and under codes easily misread as it, with only the columns that tell them apart.
- NPN transistor
- Varicap
- N-channel JFET
- Digital transistor ×2
- 3.6 V voltage detector
When more than one is left
Tap Help me choose. Up to 4 quick answers: whether the part has failed, then what separates the parts left. Those get ranked with the reasoning and a test that settles it. That uses one identification: 2 a month are free without an account, and 3 with a free account.
When you cannot read it
Tap the camera in the field. We read the characters, keep the ones we are unsure of, and search every reading. A photo too soft to read is turned back on your phone first; if it is the only one you can get, you can still send it.