390K Ohm 0.1W 0603 1% SMD Resistor

 

If your board needs a 390k ohm resistor, and the old part is a 1% 0.1W chip in a 0603 body, this is the part to order. It is a 390k ohm resistor in a small rectangular surface-mount body, built for stable, accurate work in solar inverters and other electronic circuits where a steady high value must hold. It fits voltage division, signal conditioning, and circuit protection jobs that need a fixed 390k ohm value at up to 0.1W. It does not fit jobs that need a different resistance value, a through-hole body, or more than 0.1W of power. Check the checks below before you order, so the value, the power, the voltage, and the body all match your board.

This is an original, high-quality part.

What it does

A resistor limits current and drops voltage in a circuit. A chip resistor does that job as a small flat part that solders straight onto the pads of a board, with metal ends that make the contact. This 390k ohm 1% resistor holds its 390k ohm value within 1%, so a board that calls for 390k ohm gets between 386,100 and 393,900 ohm. The 390k ohm value is a very high value: it passes only a tiny current at the same voltage, so it fits sensing, dividing, and regulation work, while the small 0603 body keeps it out of the way on crowded boards. The 0603 body is only about 1.6 mm long, so it fits boards where space is tight.

Repair techs use a part like this as a 390k ohm 0603 resistor for voltage division, where it takes a share of the voltage so the next stage sees the right level, and for signal conditioning, where a steady high resistance keeps a signal clean without loading the circuit down. It also fits circuit protection, where a fixed high value sets a safe level for the next stage. You can check the value from the marking: the 4-digit value code for this part is 3903, which reads as 390 followed by three more zeros, or 390,000 ohm.

Key features

• 390K Ohm fixed resistance, ±1% tolerance
• 0.1W power rating at 70°C ambient
• Thick film chip construction, surface mount
• 0603 body: about 1.60 mm × 0.80 mm × 0.45 mm
• Maximum working voltage 75V (series limit — this is the cap that binds for this value)
• Temperature coefficient ±100 ppm/°C
• Wide temperature range: −55°C to +155°C
• 4-digit value code 3903

Checks before you order

• Value: your board list must call for 390k ohm. A nearby value is not the same part — if your board needs a different value, stop and check the board list again. A 820k part in the same 0603 body is a different value for a different job, not a swap for this one.
• Power and heat: the power this part turns into heat must stay at or below 0.1W, and that 0.1W counts only up to 70°C ambient — above that, the safe power drops, so check the derating for your real working temperature. Work out the power from your real voltage and current (power = voltage × current) and keep it inside 0.1W with room to spare. At this high value the current is always tiny, so the power stays low in normal use — do not run it near its limit all the same.
• Voltage: the voltage across this part must stay at or below 75V in steady use. At this value the series voltage cap is the limit that binds: the power formula alone would allow about 197V, but the 75V series limit comes first. Work out the voltage from your circuit before you order.
• Tolerance: the real value may sit up to 1% away from 390k ohm. If your circuit needs tighter than 1%, this part is the wrong pick — do not hope the part you get sits near the middle.
• Body and fit: your board must take a 0603 surface-mount body. Measure the old part and match it against the pads and the space on your board. The series body is about 1.60 mm long, 0.80 mm wide, and 0.45 mm high — if your old part is much bigger, check the board list again before you order. A 7.5k part in the same 0603 body is a different value for a different job, not a swap for this one.
• Fit for the job: if your circuit only needs a fraction of a tenth of a watt, this part still works. Match the value first, then the power, then the body — a through-hole resistor is the wrong shape for a surface-mount board, even if the value matches.

Specifications

All figures below are from the maker series documents for this chip resistor family. No figure here was guessed. The maker of the exact part on this page is not stated on the live page, so the publisher should confirm the series figures against the Download file at publish time (see the gates note).

Type	Thick film chip resistor, surface mount
Resistance	390K Ohm (390,000 Ω)
Tolerance	±1% (386,100 to 393,900 ohm)
Power rating	0.1W at 70°C
Maximum working voltage	75V (series limit; this cap binds for this value — the power formula alone would allow about 197V)
Maximum overload voltage	150V
Dielectric withstanding voltage	150V (see the gates note — the second series source gives 100V)
Temperature coefficient	±100 ppm/°C
Operating temperature range	−55°C to +155°C
Marking	4-digit value code 3903 (see the gates note)
Body	1.60±0.10 × 0.80±0.10 × 0.45±0.10 mm
Derating	Full power to 70°C; derate above 70°C

Other names for the same part (good to know)

Shoppers and repair techs call this same part by a few names. 390k ohm is the plain name from its value. 390k ohm resistor is the name buyers use with the unit spelled out. 390k ohm 0603 resistor is the name buyers use when the body size matters. SMD resistor is the name for its surface-mount style. 390k ohm 1% is the short name that carries the value and the tolerance together. If your board list calls for 390k ohm at 0.1W with 1% tolerance in a 0603 body, this page is the right match. Do not judge by size alone — check the value, the power, and the tolerance too.

Frequently Asked Questions

What does 390k ohm mean?

It means 390,000 ohms of resistance. The letter K stands for kilo, or one thousand, so 390k ohm is 390 × 1,000 ohms.

What does 1% mean, and what does 0.1W mean?

1% is the tolerance: the real resistance may sit up to 1% above or below 390k ohm, so between 386,100 and 393,900 ohm. 0.1W is the power rating: the most power the part can turn into heat without damage, rated at 70°C ambient, with less allowed as it gets hotter.

What is the 3903 marking on the body?

It is the 4-digit value code for this part: 390 stands for the digits 390, and the last 3 means three more zeros, so 3903 means 390,000 ohm. The 3-digit code for the same value is 394. There is no EIA-96 code for this value, because 390 is not an E96 series value.

Can I use this part at 75 V if the power is small?

Yes, up to 75V. At 390k ohm the series voltage cap is the limit: at 75V this part uses only about 0.014W, well inside its 0.1W rating. Do not go above 75V, even though the power formula alone would allow about 197V — the 75V series limit comes first.

How do I fit a 0603 chip resistor?

Solder it onto the matching pads on the board — it has no leads, so it sits flat on the pads. Check the pad spacing against the 1.6 mm body before you solder, use a fine tip and a small amount of solder, and do not overheat the part. A magnifier helps, because the part and its marking are very small.

What is the price of this part?

Check the live price on the website. The price shown on the product page is the current one.

Use note kept from the old page: this part was listed before as a 390k ohm 0.1W 0603 SMD resistor for solar inverter applications and other electronic circuits requiring stable resistance, with 1% tolerance for minimal variation in resistance values, for compact and high-density circuit board designs, for low-power applications, widely used in solar inverters, power supplies, and other electronic equipment, for precision circuits, whether for professional or DIY projects, providing stable resistance with low noise and excellent thermal stability — and that use still stands.