470nF Capacitor in Filtering”, “Timing Circuits”, “Power Supply Units”, “PCB Layout” all anchor headings
The 470nF capacitor is one of those unassuming components that ends up in more circuit types than most engineers initially expect. It bridges the gap between the high-frequency ceramic bypass caps (think 100nF and below) and the low-frequency bulk electrolytics (1µF and above), making it genuinely useful in AC filtering stages, RC timing networks, power supply decoupling, snubber circuits, and signal coupling in audio systems. If you’ve stared at a yellow film cap or a small monolithic ceramic part stamped 474J and wondered what the code means, you’re in the right place.
Decoding the 474 Code: What Is a 470nF Capacitor?
How to Read the 3-Digit Capacitor Code
The three-digit stamping system on ceramic, film, and tantalum capacitors follows a consistent rule. The first two digits give the significant figures, the third digit is the power-of-ten multiplier, and the result is always in picofarads (pF).
For code 474:
- First two digits: 47
- Third digit: 4 → multiply by 10⁴ = 10,000
- Result: 47 × 10,000 = 470,000 pF = 470 nF = 0.47 µF
So a capacitor stamped 474J decodes as: 47 × 10,000 = 470,000 pF = 470 nF or 0.47 µF at ±5% tolerance (J suffix). This is one of the more frequently confused codes — engineers who know the 473 code (47nF) sometimes misread 474 as being just one step higher in value, not realizing the jump is ×10. Always verify before substituting.
Code 474 vs Neighboring Values
| Code | Capacitance | Also Written As |
| 472 | 4.7 nF | 4,700 pF |
| 473 | 47 nF | 0.047 µF |
| 474 | 470 nF | 0.47 µF / 470,000 pF |
| 475 | 4.7 µF | 4,700 nF |
| 476 | 47 µF | 47,000 nF |
This makes it obvious why the 473 vs 474 mix-up is so costly — substituting one for the other is a 10× error in capacitance, which will completely change the behavior of a timing circuit or filter stage.
Tolerance Letters on the 470nF Capacitor
| Suffix | Tolerance | When to Use |
| J | ±5% | Timing circuits, precision RC filters |
| K | ±10% | General decoupling, filtering, PSU bypassing |
| M | ±20% | Non-critical bypass applications |
A 474J cap gives you 470nF ±23.5nF — acceptable for most filtering and timing duties. If you receive 474K parts when you ordered 474J, the difference for a decoupling application is effectively negligible. For timing-critical designs, however, stick to J grade.
470nF Capacitor Specifications and Dielectric Types
Available Dielectric Options
The 470nF capacitor is available in multiple dielectric technologies, and choosing the right one for your specific application genuinely matters.
X7R Ceramic (MLCC): The most common 470nF part on supplier catalogs. Monolithic construction provides excellent temperature stability, low loss, and high reliability compared to standard ceramic capacitors. This non-polarized capacitor is rated at 50V and is ideal for decoupling, bypassing, filtering, and timing applications. X7R capacitance drifts ±15% over the full −55°C to +125°C temperature range and also shifts with applied DC voltage. Fine for power supply bypass but avoid it in precision timing where stability matters.
C0G / NP0 Ceramic: Excellent temperature stability and low dielectric losses, making these ideal for RF, resonant circuits, and precision filters. At 470nF, C0G parts are physically larger and more expensive than X7R equivalents but are the correct choice wherever the capacitance value needs to remain stable across temperature and voltage.
Polyester Film (PET / Mylar): The 470nF polyester film capacitor is a non-polarized capacitor using polyester film as its dielectric material. It delivers stable electrical performance, low leakage current, and long service life, making it suitable for signal coupling, filtering, and noise suppression applications. Voltage ratings of 100V, 250V, and 400V are common in radial-lead through-hole packages. The 474J 470nF 100V version in box-type epoxy casing is particularly popular for energy correction, signal filtering, and bypass applications in both analog and digital circuits.
Polypropylene Film: Best-in-class dielectric absorption performance. Available in high-voltage variants rated at 450V and 630V — a 470nF 450V polypropylene film cap is specifically suited to high-power applications. The tradeoff is physical size and cost.
Specification Comparison Table
| Dielectric | Capacitance | Voltage Rating | Tolerance | Best Application |
| X7R Ceramic (0603) | 470 nF | 10V – 50V | ±10% K | SMD decoupling, MCU bypass |
| X7R Ceramic (0805) | 470 nF | 25V – 100V | ±10% K | General SMD filtering |
| Polyester Film | 470 nF | 100V – 400V | ±5–10% | Signal coupling, audio, PSU |
| Polypropylene | 470 nF | 250V – 630V | ±5% J | High-voltage snubbers, audio |
| Monolithic Ceramic | 470 nF | 50V – 100V | ±10% K | Bypass, decoupling, timing |
The 470nF Capacitor in Filtering Applications
Where 470nF Fits in the Frequency Spectrum
A lot of engineers default to 100nF for decoupling and jump straight to 10µF electrolytics for bulk supply filtering, leaving a useful middle ground uncovered. The 470nF capacitor fills that gap. Its self-resonant frequency (SRF) — where it transitions from capacitive to inductive behavior — sits comfortably in the 1–5 MHz range for through-hole film parts and higher for 0603/0805 MLCC packages. That makes it effective at filtering noise in the tens-of-kilohertz to low-megahertz range that 100nF caps handle poorly and electrolytics simply can’t reach.
RC Filter Cutoff Frequencies with 470nF
Using the standard formula f = 1 / (2π × R × C) with C = 470nF (0.00000047 F):
| Resistor Value | Cutoff Frequency (-3dB) | Practical Application |
| 10 Ω | ~33.9 kHz | Output EMI filter, switching PSU |
| 100 Ω | ~3.4 kHz | Audio low-pass, anti-aliasing |
| 330 Ω | ~1.03 kHz | Audio crossover mid frequency |
| 1 kΩ | ~339 Hz | Bass rolloff, sub-woofer filter |
| 3.3 kΩ | ~102 Hz | Power line frequency filtering |
| 10 kΩ | ~33.9 Hz | Very-low-frequency rejection |
| 33 kΩ | ~10.2 Hz | Near-DC coupling and blocking |
These values make the 470nF a natural fit for audio-band low-pass filters, anti-aliasing stages ahead of ADCs sampling in the tens-of-kHz range, and AC-line EMI rejection in power supply input stages.
470nF Capacitor in Timing Circuits
RC Time Constants and the 555 Timer
The RC time constant formula is simply τ = R × C. With a 470nF capacitor, here’s what common resistor values produce:
| Resistor Value | RC Time Constant (τ) | 555 Monostable Pulse Width (T = 1.1RC) |
| 1 kΩ | 470 µs | ~517 µs |
| 4.7 kΩ | 2.21 ms | ~2.43 ms |
| 10 kΩ | 4.7 ms | ~5.17 ms |
| 47 kΩ | 22.1 ms | ~24.3 ms |
| 100 kΩ | 47 ms | ~51.7 ms |
| 470 kΩ | 221 ms | ~243 ms (≈ ¼ second) |
| 1 MΩ | 470 ms | ~517 ms (≈ ½ second) |
The 555 timer IC monostable output pulse width is calculated as T = 1.1 × R × C — a 470nF capacitor paired with a 470kΩ resistor gives approximately 243 milliseconds, which is handy for LED flash timers, switch debounce circuits, and relay delay applications without needing a large electrolytic capacitor. Unlike electrolytics, film capacitors have far lower leakage current, so a 470nF film cap with a high-value resistor gives noticeably more accurate timing than an electrolytic of equivalent value.
Why Avoid Electrolytic Capacitors in Timing Circuits?
This is worth spelling out clearly. Electrolytic capacitors have significant leakage current that causes the effective charge/discharge time to differ from the theoretical calculation — particularly at higher resistor values where the leakage represents a meaningful fraction of the current flowing through the timing resistor. A 470nF polyester film capacitor avoids this problem entirely. It’s non-polarized, has very low leakage, and will maintain timing accuracy well within the J-grade ±5% tolerance over the operating temperature range.
470nF Capacitor in Power Supply Units (PSU)
PSU Input Stage Filtering and X-Capacitors
In AC mains power supply designs, capacitors connected directly across the AC input line to suppress differential-mode conducted EMI are known as X-capacitors. A 470nF X2-rated film capacitor at the mains input is a common specification in switch-mode power supplies and motor drives. The X2 rating indicates the capacitor is specifically approved for use across the mains line, with defined failure modes that don’t create a shock hazard. These parts typically carry IEC 60384-14 certification and are rated for 250V AC or 305V AC continuous operation.
Output Stage Decoupling and Ripple Filtering
A capacitor on a PCB at the output stage of a linear or switching regulator serves a different purpose from the bulk electrolytic. Where the bulk cap handles low-frequency ripple, a 470nF ceramic or film cap placed close to the output pin handles the higher-frequency transients that the electrolytic misses due to its own parasitic inductance at frequencies above a few hundred kHz. The combination of a 47µF or 100µF electrolytic in parallel with a 470nF ceramic provides substantially lower impedance across a wider bandwidth than either part alone.
Snubber and Transient Suppression Roles
Across diode and MOSFET junctions in a switching power supply, a 470nF capacitor in series with a damping resistor forms a classic RC snubber. The capacitor absorbs the energy stored in circuit parasitic inductance during switch-off transitions, preventing voltage spikes that would otherwise stress the switching device. A 470nF polypropylene film cap rated at 630V has enough headroom for most off-line flyback and forward converter topologies operating from a 230V AC rectified rail. At high frequencies, multilayer capacitors exhibit low ESR and find conventional use as snubbers or filters in telecommunications, medical, military, and aerospace equipment.
PCB Layout Considerations for 470nF Capacitors
Through-Hole vs SMD: Making the Right Choice
Through-hole 470nF film capacitors are the correct pick whenever you need the higher voltage ratings (250V+), lower dielectric absorption (polypropylene), or non-polarized signal-path coupling. The main PCB layout consideration is lead spacing — radial 474 film caps come in 5mm, 7.5mm, and 10mm pitch variants. Getting this wrong on your footprint means reworking leads manually or spinning the board, so always verify the datasheet before finalizing the PCB footprint.
For standard 5V/3.3V digital supply bypass duty, 0603 or 0805 SMD MLCC 470nF parts make more engineering and manufacturing sense. Their low ESL (roughly 0.5–1.5 nH for 0603 parts) pushes the self-resonant frequency well above 10 MHz, and their small footprint allows placement within 1–2 mm of IC power pins where bypass performance is maximized.
Multi-Layer Ceramic Capacitors: Beware DC Bias Derating
This catches engineers off guard more often than it should. An X7R 470nF MLCC rated at 10V will lose 30–50% of its nominal capacitance at 5V due to DC bias derating — meaning your effective bypass capacitance is closer to 250–330nF under typical operating conditions. For critical filtering applications, either specify a higher voltage rating (a 25V or 50V part on a 5V rail retains nearly full capacitance) or use a C0G dielectric which doesn’t exhibit this behavior.
Useful Resources for 470nF Capacitor Selection
- Capacitor Code Calculator: kiloohm.info/3-digit-capacitor/474 — Decode or encode any 3-digit capacitor code including 474
- Murata SimSurfing: product.murata.com/en-global/tools/simsurfing — Plot actual impedance vs. frequency curves for 470nF MLCCs including DC bias derating
- KEMET Component Selector: kemet.com — Comprehensive catalog of film and ceramic 470nF capacitors with full datasheets and SPICE models
- WIMA Film Capacitor Catalog: wima.de — Premium German film capacitors; the MKS2 and MKP series cover 470nF in multiple voltage and lead spacing options
- 555 Timer Calculator (Digi-Key): digi-key.com/en/resources/conversion-calculators/conversion-calculator-555-timer — Calculate timing intervals with 470nF for monostable and astable 555 configurations
- IEC 60384-14 Standard Reference — The governing document for X-capacitor and Y-capacitor ratings in AC mains applications
Frequently Asked Questions About the 470nF Capacitor
Q1: What does a capacitor marked 474 mean, and what is its actual value? Code 474 decodes as 47 × 10⁴ pF = 470,000 pF = 470 nF = 0.47 µF. These four notations describe the exact same capacitance value. If a supplier’s catalog shows “0.47µF 474J”, it is referring to this same part. The letter J at the end indicates ±5% tolerance, K indicates ±10%.
Q2: Can I replace a 474J capacitor with a 474K in an audio circuit? The tolerance difference between J (±5%) and K (±10%) represents a maximum spread of only 47nF for this value — from 423nF to 517nF for K grade vs 447nF to 493nF for J grade. In most audio signal coupling and filter applications, this difference is inaudible and the K-grade substitution is electrically sound. Where the cap is setting a specific RC corner frequency or timing interval that is close to a performance boundary, stick with J grade.
Q3: Is a 470nF capacitor polarized? No. Whether ceramic, polyester film, or polypropylene, 470nF capacitors are non-polarized and can be installed in either orientation on a PCB. This makes them directly suitable for AC signal path coupling, crossover networks, and AC mains X-capacitor applications where polarized electrolytics cannot be used. Always confirm that an X-rated film capacitor carries the appropriate safety certification before deploying it across AC mains lines.
Q4: What is the difference between a 470nF capacitor and a 0.47µF capacitor? They are exactly the same value expressed in different units. 470 nanofarads = 0.47 microfarads = 470,000 picofarads. Supplier catalogs and datasheets use all three notations interchangeably, which causes confusion when searching for parts. When placing orders, entering “0.47µF” and “470nF” in a supplier’s search field should return identical results for the same capacitor type.
Q5: Why does my 470nF X7R MLCC measure significantly less than 470nF on my bench meter? Two main reasons. First, DC bias derating: if you’re measuring with a DC bias applied (as would occur in circuit), an X7R MLCC rated at 10V can lose 40–50% of capacitance at voltages above half its rating. Second, capacitance meters typically measure at a fixed low-voltage AC test signal (often 1V RMS at 1kHz), which doesn’t reflect real-world circuit behavior with a DC supply rail. The solution is to either specify a higher-voltage-rated MLCC — a 25V part on a 5V rail retains close to its full capacitance — or switch to C0G dielectric, which shows negligible voltage-dependent capacitance change.
The 470nF capacitor punches well above its weight class. From RC timing networks producing quarter-second pulses with nothing but a resistor, to X-capacitor EMI filtering at the AC mains input, to power supply output decoupling that electrolytics can’t cover — it’s the kind of component that rewards engineers who understand exactly what it’s doing and exactly where it belongs on the board.
