39 Ohm 0.25W 1206 1% SMD Resistor

 

If your board needs a 39 ohm resistor, and the old part is a 1% 0.25W chip in a 1206 body, this is the part to order. It is a 39 ohm resistor in a small rectangular surface-mount body, built for precise power regulation and signal control in solar inverters and other power electronics where a steady low value must hold. It fits power regulation, signal control, and circuit protection jobs that need a fixed 39 ohm value at up to 0.25W. It does not fit jobs that need a different resistance value, a through-hole body, or more than 0.25W 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 39 ohm 1% resistor holds its 39 ohm value within 1%, so a board that calls for 39 ohm gets between 38.61 and 39.39 ohm. The 39 ohm value is a low value: at the same voltage it passes far more current than a high-value part, so it fits current limiting and power work, while the 0.25W rating in the 1206 body gives it more room for heat than the smaller 0603 parts. The 1206 body is about 3.1 mm long, so it fits boards where a larger part would not.

Repair techs use a part like this as a 39 ohm 1206 resistor for power regulation, where it holds the current through a stage to a safe level, and for signal control, where a steady low resistance keeps a signal clean and stable. It also fits circuit protection, where a fixed low 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 3900, which reads as 39 followed by no more zeros, or 39 ohm.

Key features

• 39 Ohm fixed resistance, ±1% tolerance
• 0.25W power rating at 70°C ambient
• Thick film chip construction, surface mount
• 1206 body: about 3.10 mm × 1.60 mm × 0.55 mm
• Maximum working voltage 200V (series limit — the 0.25W rating caps this value at about 3.1V)
• Temperature coefficient ±100 ppm/°C
• Wide temperature range: −55°C to +155°C
• 4-digit value code 3900

Checks before you order

• Value: your board list must call for 39 ohm — not 39k ohm, which would be 39,000 ohm and a completely different part. A nearby value is not the same part — if your board needs a different value, stop and check the board list again. A 2m part in the same 1206 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 0.25W, and that 0.25W 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 0.25W with room to spare. This is a low-value part, so even a small voltage across it makes real power — do not run it near its limit.
• Voltage: the voltage across this part must stay at or below about 3.1V in steady use. At this value the power rating is the real limit: at 200V the part would use about 1,026W, far above its rating, even though 200V is the series voltage limit. Work out the voltage from your circuit before you order.
• Tolerance: the real value may sit up to 1% away from 39 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 1206 surface-mount body. Measure the old part and match it against the pads and the space on your board. The series body is about 3.10 mm long, 1.60 mm wide, and 0.55 mm high — if your old part is much smaller, check the board list again before you order. A 27 ohm part in the same 1206 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 quarter 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	39 Ohm (39 Ω)
Tolerance	±1% (38.61 to 39.39 ohm)
Power rating	0.25W at 70°C
Maximum working voltage	200V (series limit; the 0.25W rating caps this value at about 3.1V)
Maximum overload voltage	400V
Dielectric withstanding voltage	500V (see the gates note — the second series source gives 300V)
Temperature coefficient	±100 ppm/°C
Operating temperature range	−55°C to +155°C
Marking	4-digit value code 3900 (see the gates note)
Body	3.10±0.10 × 1.60±0.10 × 0.55±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. 39 ohm is the plain name from its value. 39 ohm resistor is the name buyers use with the unit spelled out. 39 ohm 1206 resistor is the name buyers use when the body size matters. SMD resistor is the name for its surface-mount style. 39 ohm 1% is the short name that carries the value and the tolerance together. If your board list calls for 39 ohm at 0.25W with 1% tolerance in a 1206 body, this page is the right match. Do not judge by size alone — check the value, the power, and the tolerance too. And do not mix this part up with a 39k ohm part: 39k means 39,000 ohm, which is a thousand times more.

Frequently Asked Questions

What does 39 ohm mean?

It means 39 ohms of resistance. Ohm is the unit of resistance, so a 39 ohm part resists current flow by 39 ohms. It is not 39k ohm — 39k would mean 39,000 ohms.

What does 1% mean, and what does 0.25W mean?

1% is the tolerance: the real resistance may sit up to 1% above or below 39 ohm, so between 38.61 and 39.39 ohm. 0.25W 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 3900 marking on the body?

It is the 4-digit value code for this part: 39 stands for the digits 39, and the last 0 means no more zeros, so 3900 means 39 ohm. The 3-digit code for the same value is 390. There is no EIA-96 code for this value, because 39 is not an E96 series value.

Can I use this part at 200 V if the power is small?

No. At 39 ohm the 0.25W rating is the limit that matters: it caps the steady voltage at about 3.1V. At 200V this part would use about 1,026W, far above its rating. The 200V figure is the series voltage limit, not a voltage you can use at this value.

How do I fit a 1206 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 3.1 mm body before you solder, use a fine tip and a small amount of solder, and do not overheat the part.

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 39 ohm 1206 SMD resistor, a high-precision surface-mount component for efficient power regulation and signal control in electronic circuits including solar inverters, with 1% tolerance for reliable and stable performance, minimal power loss and better energy efficiency, in a compact 1206 package for densely packed circuit boards, with excellent thermal stability and long-term durability, built to withstand varying temperatures and voltage fluctuations, for solar inverters, power supplies, and other industrial electronics, with low noise, excellent moisture resistance, and high reliability, for optimal efficiency and circuit protection — and that use still stands.