Solve fc, R or C
API · /rcfilter-api
RC Filter API
healthy
4,175 Subscribers
First-order RC and RL passive-filter design as an API, computed locally and deterministically. The lowpass and highpass endpoints take a resistor and capacitor (RC) or a resistor and inductor (RL) and return the −3 dB cutoff frequency (fc = 1/(2πRC) for RC, R/(2πL) for RL), the time constant (τ = RC or L/R) and the angular cutoff; pass a frequency as well and they add the magnitude response as a linear gain and in decibels and the phase shift in degrees — a 1 kΩ / 1 µF low-pass has fc ≈ 159.15 Hz, and right at the cutoff the gain is −3.01 dB with −45° phase for a low-pass or +45° for a high-pass. The component endpoint solves the missing one of fc, R and C from the other two (fc = 1/(2πRC)), so you can size a resistor or capacitor for a target cutoff. All quantities are SI: ohms, farads, henries and hertz. Everything is computed locally and deterministically, so it is instant and private. Ideal for electronics, audio, embedded, signal-processing and EE-education app developers, filter-design and circuit-sizing tools, and maker software. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is first-order single-pole filter design; for full RLC impedance and resonance use an impedance API and for stored capacitor energy a capacitor API.
api.oanor.com/rcfilter-api
API health
healthy- Uptime
- 100.00%
- Server probes · 24h
- Avg latency
- 78 ms
- Server probes · 24h
- Subscribers
- 4,175
- active
- Total calls
- 76
- last 7 days
Pricing
Pick a tier — billed monthly, cancel anytime.
Free
Free
- 4,600 calls / month
- 2 requests / second
- Hard cap (429 above quota, no overage)
- 4,600 calls/month
- 2 req/sec
- Low-pass + high-pass + component solver
- No credit card
Starter
€5.50 /month
- 46,000 calls / month
- 6 requests / second
- Hard cap (429 above quota, no overage)
- 46,000 calls/month
- 6 req/sec
- RC & RL, gain/phase response
- Email support
Pro
€16.00 /month
- 215,000 calls / month
- 15 requests / second
- Hard cap (429 above quota, no overage)
- 215,000 calls/month
- 15 req/sec
- Audio & embedded design pipelines
- Priority support
Mega
€49.00 /month
- 1,290,000 calls / month
- 40 requests / second
- Hard cap (429 above quota, no overage)
- 1,290,000 calls/month
- 40 req/sec
- Platform scale
- Dedicated SLA
Built by
Related APIs
Other APIs with overlapping tags.
AC Resonance & Reactance API
AC reactance and LC/RC tuning maths as an API, computed locally and deterministically. The reactance endpoint computes the capacitive reactance Xc = 1/(2πfC) and the inductive reactance Xl = 2πfL at a given frequency, and — when both a capacitor and an inductor are supplied — the net series reactance X = Xl − Xc, whether the circuit looks inductive, capacitive or resonant, and the impedance magnitude. The resonant endpoint computes the LC resonant frequency f₀ = 1/(2π√(LC)), or, given a target frequency and one component, solves the other component you need to tune to it. The cutoff endpoint computes the RC or RL filter cutoff frequency — fc = 1/(2πRC) for RC, fc = R/(2πL) for RL — and the time constant. Frequencies are in hertz; capacitance, inductance and resistance accept SI base units with handy µF/nF/pF and mH/µH inputs. Everything is computed locally and deterministically, so it is instant and private. Ideal for electronics, RF, audio-filter and embedded app developers, tuning and filter-design tools, and electronics education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is AC reactance & LC/RC tuning; for LED series-resistor sizing use an LED-resistor API and for VSWR and impedance match use a VSWR API.
api.oanor.com/resonance-api
Newegg API
Live product search from Newegg.com, the major electronics & tech retailer. Search any keyword — laptop, rtx 4070, ssd — and get the product listings with title, brand, model, current price, original price, image, rating, review count, in-stock status, seller and the Newegg product URL. Prices are live USD. Ideal for shopping, price-comparison, deal-tracking and e-commerce dashboards.
api.oanor.com/newegg-api
RTD Pt100 Sensor API
RTD (resistance-temperature-detector) sensor maths as an API, computed locally and deterministically with the IEC 60751 Callendar–Van Dusen equation — the resistance, temperature and tolerance numbers an instrumentation or controls engineer reads a Pt100 or Pt1000 with. The resistance endpoint gives the sensor resistance from temperature: above 0 °C, R = R₀·(1 + A·T + B·T²) with A = 3.9083×10⁻³ and B = −5.775×10⁻⁷; below 0 °C a third term adds C·(T−100)·T³ — a standard Pt100 (100 Ω at 0 °C) reads 138.51 Ω at 100 °C and 80.31 Ω at −50 °C, and a Pt1000 is ten times that. The temperature endpoint inverts it to turn a measured resistance back into temperature — analytically above 0 °C, iteratively below — exactly what a transmitter does with the bridge reading, and a reminder that a 3- or 4-wire connection cancels the lead-wire resistance so it does not read as extra degrees. The tolerance endpoint gives the IEC 60751 accuracy band in both °C and Ω by class — AA ±(0.10 + 0.0017·|T|), A ±(0.15 + 0.002·|T|), B ±(0.30 + 0.005·|T|), C ±(0.60 + 0.010·|T|) — the error growing with distance from 0 °C. Everything is computed locally and deterministically, so it is instant and private. Ideal for instrumentation and controls software, data-logger and transmitter firmware, calibration and industrial-IoT tools. Pure local computation — no key, no third-party service, instant. 3 compute endpoints. For NTC thermistors use a thermistor API; for thermocouples a thermocouple API.
api.oanor.com/rtd-api
Voltage Divider API
Resistive voltage-divider circuit design as an API, computed locally and deterministically. The divide endpoint takes an input voltage and two resistors and returns the output voltage Vout = Vin·R2/(R1+R2), the current I = Vin/(R1+R2) that flows through the chain, and the power dissipated in each resistor and in total — a 12 V source with R1 = 1 kΩ and R2 = 2 kΩ gives 8 V at 4 mA. The loaded endpoint adds a load resistor across R2, computes the parallel combination R2′ = R2·RL/(R2+RL) and the loaded output Vout = Vin·R2′/(R1+R2′), and reports the droop in volts and percent against the unloaded value, the classic mistake when a divider feeds a real load. The resistor endpoint sizes the missing resistor for a target output — R2 = R1·Vout/(Vin−Vout) or R1 = R2·(Vin−Vout)/Vout — so you can pick parts for a reference or sensor-bias point. All quantities are volts, ohms, amps and watts. Everything is computed locally and deterministically, so it is instant and private. Ideal for electronics, embedded, hardware, sensor-interfacing and EE-education app developers, reference-voltage and bias-network tools, and maker software. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is the resistive divider; for a single Ohm’s-law relationship use an Ohm’s-law API and for RC/RL filters an RC-filter API.
api.oanor.com/voltagedivider-api
Frequently asked questions
Quick answers about pricing, quotas, and integration.
How do I get an API key for RC Filter API?
Sign up for free at oanor.com, generate an API key from the developer dashboard, and call RC Filter API with the x-oanor-key header. No credit card needed for the free tier.
What's the rate limit for RC Filter API?
Free tier allows 1 request per second. Paid plans scale up to 50 requests per second on the Mega tier. Hard limits return HTTP 429 above the quota — no surprise overage charges.
How much does RC Filter API cost?
RC Filter API has a free tier with 100 calls / month. Paid plans start at €5.50 / month with higher quotas and faster rate limits.
Can I cancel my subscription anytime?
Yes. Plans are billed monthly and you can cancel anytime from your billing dashboard. No long-term contracts and no cancellation fee.
Is RC Filter API GDPR-compliant?
All requests to RC Filter API go through our EU-based gateway. Your upstream API key never leaves our server and no personal data is shared with the upstream provider beyond the request you send.
Pick an endpoint from the list on the left to see its details and try it.
Code snippets
Sign up to get an API key, then call any path under your slug.
curl https://api.oanor.com/rcfilter-api/SOME_PATH \
-H "x-oanor-key: oanor_test_..."const res = await fetch("https://api.oanor.com/rcfilter-api/SOME_PATH", {
headers: { "x-oanor-key": "oanor_test_..." }
});
const data = await res.json();$ch = curl_init("https://api.oanor.com/rcfilter-api/SOME_PATH");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-oanor-key: oanor_test_..."]);
$response = curl_exec($ch);import requests
r = requests.get(
"https://api.oanor.com/rcfilter-api/SOME_PATH",
headers={"x-oanor-key": "oanor_test_..."},
)
print(r.json())Ratings
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