3.3 Ohm 1/2W 5% Carbon Film Fixed Resistor

If your board needs a 3.3 ohm resistor for real current, and the old part is a 1/2W carbon film part with 5% tolerance, this is the part to order. It is a 3.3 ohm resistor in an axial through-hole body, built for current limiting and voltage regulation where a small signal resistor would run too hot. It fits power supplies, inverter repair, and general circuit work that needs a fixed 3.3 ohm value at up to 1/2W. It does not fit jobs that need a different resistance value, a surface-mount body, or more than 1/2W of power. Check the checks below before you order, so the value, the power, the current, 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 carbon film resistor does that job with a thin carbon layer on a ceramic rod, which gives steady, low-noise performance for standard circuit work. This 3.3 ohm 1/2w resistor holds its 3.3 ohm value within 5%, so a board that calls for 3.3 ohm gets between 3.135 and 3.465 ohms. The low value is the point here: at the same voltage, a 3.3 ohm part passes far more current than a high-value part, which is why it fits current control and load work rather than signal work. The 1/2W rating means it can turn up to half a watt into heat without damage, as long as the current limit below is respected.

Repair techs use a part like this as a 3.3 ohm resistor for current limiting, where it holds current to a safe level, and for voltage regulation, where it takes a share of the voltage so the next stage sees the right level. It also fits circuit protection and load balancing, where a fixed low resistance sets how much current a branch can draw. It is an axial resistor, so it mounts through holes on a board, not on the surface. Its colour bands are orange, orange, gold, gold.

Key features

• 3.3 Ohm fixed resistance, ±5% tolerance
• 1/2W power rating at 70°C ambient
• Carbon film construction for steady, low-noise work
• Axial leads for through-hole mounting on PCBs and breadboards
• Maximum working voltage 300V (see the current limit in the checks)
• Temperature coefficient −500~+350 ppm/°C
• Wide temperature range: −55°C to +155°C

Checks before you order

• Value: your board list must call for 3.3 ohm. A nearby value is not the same part — 33 ohm is ten times bigger, and 0.33 ohm is ten times smaller, so read the value twice. If your board needs a different value, stop and check the board list again. A 1K part in the same family is a different job, not a swap for this one.
• Power and current: the power this part turns into heat must stay at or below 1/2W, and that 1/2W counts only up to 70°C ambient — above that, the safe power drops toward zero at 155°C. For a low-value part like this one, current is the limit to watch: do not push more than about 0.39 A through it. Work out the current from your real voltage and resistance (current = voltage ÷ resistance) and keep it inside that limit with room to spare.
• Voltage: the voltage across this part must stay inside the 300V series cap. From power alone the working voltage for a 3.3 ohm part at 1/2W is only about 1.3V, so in normal use the voltage stays far below the cap — the current limit above is what binds. Above 300V, this part is the wrong pick.
• Tolerance: the real value may sit up to 5% away from 3.3 ohm. If your circuit needs tighter than 5%, this part is the wrong pick — do not hope the part you get sits near the middle.
• Body and fit: your board must take an axial through-hole body. Measure the old part and match it against the holes and the space on your board. The series normal-style body for a 1/2W part is about 9.0 mm long and 3.3 mm across — if your old part is much bigger, check the board list again before you order.
• Fit for the job: if your circuit only needs a tiny current, this part still works, but a high-value 51K part is a different job, not a swap for this one. Match the value first, then the power, then the body.

Specifications

All figures below are from the maker series documents for this 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).

Other names for the same part (good to know)

Shoppers and repair techs call this same part by a few names. 3.3 ohm resistor is the plain name from its value. 3.3 ohm 1/2w resistor is the name buyers use when the power rating matters. Carbon film resistor is the name for its construction type. Axial resistor is the name for its lead style. 3.3 ohm 5% is the short name that carries the value and the tolerance together. If your board list calls for 3.3 ohm at 1/2W with 5% tolerance in an axial 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 3.3 ohm mean?

It means 3.3 ohms of resistance. It is a low value, so it passes a fairly large current for its size and is used where current must be set or limited, not where a signal must be blocked.

What does 1/2W mean, and what does 5% mean?

1/2W 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. 5% is the tolerance: the real resistance may sit up to 5% above or below 3.3 ohm, so between 3.135 and 3.465 ohms.

How much current can this part carry?

About 0.39 A at most, from the 1/2W rating and the 3.3 ohm value. That is a calculated limit, not a guess — work out your real current first (current = voltage ÷ resistance) and keep it below that with room to spare.

Can I use a different value, like 33 ohm?

No, not without checking the circuit. 33 ohm is ten times the resistance, so the current and the voltage drop change completely. Only swap in a different value if the circuit design allows it — otherwise match the board list exactly.

How do I read the colour bands?

Orange, orange, gold, gold. The first two bands give the digits 3 and 3, the gold band means multiply by 0.1, which gives 3.3 ohm, and the last gold band means ±5% tolerance.

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 high-precision component for circuit stability and efficiency in solar inverter repairing and other electronic applications, for accurate current control and voltage regulation, circuit protection, power management, and load balancing, with carbon film construction for low noise and thermal stability in sensitive power circuits and axial leads for easy mounting, used in home appliances, communication, instruments, and electronic equipment, for inverter maintenance, power supplies, and general electronic circuits — and that use still stands.