2-layer 75×66mm RED KOMODO-X power and IO distribution board with dual input ORing, protected switched bus, 3.3V logic rail, edge solder-pad flying-lead terminals, and split ground star-point architecture.

Cortex v0 tiny AI wearable schematic: Raytac MDBT53V-1M BLE/nRF5340 module, USB-C LiPo charging, TPS63020 3.3V buck-boost, dual microphones, QSPI flash, tactile button, and WS2812B LED on a ~30mm round 4-layer PCB.

Best-effort NF-UNIVERSAL ALARM schematic recreation from image, with MCP73831 Li-ion charging, dual 555 timers, transistor switching, LEDs, switches, and flagged uncertainties.

4-layer dual PCA9685 servo controller for Raspberry Pi 5 and STM32 Nucleo with 20A servo power distribution

ESP32-based automatic Normal Saline Solution warmer with dual DS18B20 temperature sensing, ILI9341 TFT display, relay-controlled 12V heater output, buzzer/LED alerts, push button input, and segregated high-current PCB layout for thesis prototyping.

Best-effort NF-UNIVERSAL ALARM schematic recreation from image, with MCP73831 Li-ion charging, dual 555 timers, transistor switching, LEDs, switches, and flagged uncertainties.

Analog noise cancellation circuit migrated from EasyEDA PCB JSON using LM358 dual op-amps, 12V single-supply operation, virtual ground biasing, notch/filter network, input/output terminal blocks, and PCB preparation for manufacturing review.

5V 5A power board with eFuse-protected Raspberry Pi rail and dual MOSFET-controlled motor outputs with transient and surge protection.

Portable potentiostat PCB with low-noise analog front end, dual 3.3 V rails, and 4-layer mixed-signal layout for heavy-metal voltammetry.

Compact ESP32-S3 AI robot controller with DevKitC-1 module, 2S Li-ion power input, 5V buck regulator, optional clean 3.3V rail, TB6612FNG dual motor driver, OV2640 camera FPC, I2S audio, OLED, ultrasonic and TCRT5000 sensor headers, and a compact 2-layer PCB prepared for Gerber export.

STM32F401 Blackpill-style railway crossing safety controller with dual 12V input selection, LM2596 5V buck, AMS1117-3.3 MCU rail, horn relay driver, and edge-mounted off-board sensor, servo, and UART connectors for modular prototyping.

ESP32-S3 door access controller with USB-C Li-ion charging, VBAT and 12V lock power, dual 3.3V rails, I2C sensor headers, reed/PIR inputs, LED indicators, buzzer, and MOSFET plus relay lock outputs. External modules and field devices remain represented by connector placeholders with documented pinouts for later PCB and validation work.

This tiny board is an easy way to use Toshiba’s TB6612FNG dual motor driver, which can independently control two bidirectional DC motors or one bipolar stepper motor. A recommended motor voltage of 4.5 V to 13.5 V and peak current output of 3 A per channel (1 A continuous) make this a great motor driver for low-power motors. #Module #Motor-Driver #TB6612FNG

Two-channel symmetric line follower robot, dual CNY70 sensor front-end with mirrored 2N2222A motor drive stages and central 8V battery input

FlowState Headband EVT1 — 4-Channel EEG Calibration Device Closed-loop EEG neurofeedback headband for theta/beta baseline calibration. 4-layer mixed-signal PCB, 40x30mm. Core ICs: - ADS1299-4PAG (TI) — 4-channel 24-bit EEG analog front end, SPI interface, 250 SPS - nRF5340 (Nordic) — Dual-core BLE 5.3 SoC, 128 MHz app core + 64 MHz network core Key requirements: - Separate analog and digital power domains (dual LDO: LP5907 for AVDD, AP2112 for DVDD) - Split analog/digital ground planes with single-point connection - 6 electrode inputs (4 active + 1 reference + 1 DRL) with individual TVS ESD protection on each - LIS2DH12 accelerometer (I2C) for motion artifact detection - MCP73831 USB-C battery charging (300-500 mAh LiPo) - 2.4 GHz chip antenna or PCB trace antenna at board edge with 10mm keepout - Conformal coating for sweat/moisture protection Reference designs: - Analog front-end: TI ADS1299 EVM (SBAS499) - Digital/BLE: Nordic nRF5340 DK reference schematic Critical constraint: Microvolt-level EEG signals — analog input routing and power supply filtering are the highest-priority layout concerns.

Industrial dual motor controller using an ESP8266 NodeMCU and L298N dual H-bridge for 2x 12V 2A DC motors, with MQTT remote control, manual override buttons, 5-bit DIP addressing, reset input, status LEDs, SS34 reverse-polarity protection, 5A fuse, LM2596 5V buck conversion, TVS surge protection, and future expansion provisions for INA219 current sensing, OTA firmware, RS485, and enclosure integration.

MagicGlow smart key tray annular PCB with dual WS2812B rings, ESP32-C6 control, HX711 load-cell interface, USB-C power/UART access, buzzer, and button.

Preamplificador dual de bajo ruido para contrabajo con dos canales piezo independientes: canal UP con sensor LDTM-028K y canal DOWN con dos LDT0-028K en paralelo, alimentado con batería de 9 V y usando exclusivamente OPA1642. Incluye buffers de entrada de ultra alta impedancia (>=20 MOhm), control de ganancia independiente, filtrado HPF 20-30 Hz y LPF 15-18 kHz, ecualización activa de 3 bandas por canal, protección contra inversión de polaridad, filtrado RF en entradas, desacoplo 100 nF + 10 uF por rail por amplificador, topología de star ground, salidas SMA separadas compatibles con Fishman Presys Blend 301, objetivo de consumo total <5 mA, impedancia de salida <3.5 kOhm, nivel nominal de salida 0.25 V RMS y máximo 1 V RMS sin distorsión. Diseño listo para PCB y fabricación con enfoque de ruido mínimo.

Single-project implementation of the Blue Ant AMP Architecture Rev2 using one shared schematic with six logical board partitions: PCB-01 phono stage, PCB-02 input selector and relay attenuator interface, PCB-03 balanced driver and RCA-to-balanced conversion interface, PCB-04 dual logical power amplifier channels, PCB-05 multi-rail power supply, and PCB-06 isolated control and display. Explicit inter-partition connector interfaces and named nets preserve balanced signal handling after RCA conversion, distinct rail domains (+63V, -63V, +15V, -15V, +5V, +3.3V), and documented hard constraints including low-noise analog isolation and high-voltage domain separation.

AI-SBC: compact high-lane-count compute board with 4x M.2 NVMe, dual PCIe Gen5 x16 slots, dual-input power ORing + eFuse, VRM rail placeholders, rich IO panel, and Arduino header area

SmartDeskPet v1.0 Shield Stage 1 status: - Goal: 5V input -> dual AMS1117-3.3 rails (+3V3_MCU and +3V3_WIFI) with common GND. - Note: Keep power nets explicitly named (avoid unnamed nets) to keep ERC happy. Stage 1 completion checklist: - Mark J1 Pin_1 (+5V) as a Power Output pin to satisfy ERC power-driver checks. - Verify all GND symbols/returns are on the same GND net. - Keep +5V_SERVO isolated from the main +5V net (only share GND). Stage 2 preparation notes (MPN/LCSC + layout constraints): - MPN/LCSC targets to define before Stage 2 exit: - AMS1117-3.3 (SOT-223): set exact MPN and (optionally) LCSC PN for both U1 and U2. - 100nF capacitor (0603): set MPN/LCSC for all 0603 100nF decouplers. - 4.7k resistor (0603): set MPN/LCSC for I2C pull-ups R1 and R2. - 1000uF bulk capacitor (radial): set MPN/LCSC for C7 (CP_Radial_D10.0mm_P5.00mm). - DC005 power jack/regulator input: select exact DC005 footprint + MPN/LCSC (if used). - 2.54mm headers/sockets: set MPN/LCSC for H1, H2, J1, J3, J4, J5, P3, P4, P5, and J2. - ESP-01S antenna keepout: - Reserve a copper keepout under and in front of the ESP-01S onboard antenna. - No copper pours/traces/components in the antenna region (top and bottom) per module guidelines. - H1/H2 header spacing: - Maintain 1000 mil spacing between H1 and H2 header centerlines (shield mechanical requirement). - Silkscreen placeholders: - Add silkscreen labels for: 5V IN, GND, +3V3_MCU, +3V3_WIFI, SERVO1, SERVO2, I2C SDA/SCL, DHT11, ASRPRO UART2, ESP-01S UART3. - Add placeholder text for: MPN, LCSC, board revision, and date code. Stage 3 layout constraints (placement and routing guidance): - Connector placement strategy: - Place H1 and H2 first to lock the shield mechanical interface; enforce 1000 mil spacing. - Place J1 and any DC005 input at the board edge for easy access. - Designated power area planning: - Group U1, U2, and C7 near the 5V entry point; keep high-current 5V and regulator loops short. - Use wide copper for +5V and any servo supply; stitch GND around power section. - Antenna keepout boundaries: - Place J2 (ESP-01S socket) at a board edge with the antenna facing outward. - Enforce a top-and-bottom copper keepout in the antenna region; keep noisy power traces away.

40×30 mm 4-Layer FCBoard with dual JST-GH 1.25 mm top-entry GH-6 connectors for PWR1/PWR2, SWD 1.27 mm debug-only connector, dual 5 V ideal-diode ORing, isolated USB_5V, dedicated nets (PWR1_5V, PWR2_5V, 5V_IO, 5V_SENS, 3V3_MCU, 3V3_IMU_A/B/C), per-IMU LDOs with inline ferrites and decoupling, and MCU VDDA ferrite isolation #JSTGH #CubeGrade #PowerArchitecture #FCBoard

3.3V ESP32-S3 Dual 6V Rail MOSFET Board with MCP23017 I2C Expanders, Option C Gate Network, SW2 DPST Rail-Interlock, 2S LiFePO4 Charger/BMS (BQ24618 + BQ29209) with Series Battery Wiring and Charge Integration, and 2×10 RA Headers (#MCP23017_3V3 #OptionC #GateNetwork #RailInterlock #Dual6V #BQ24618 #BQ29209 #2S #LiFePO4 #SeriesBattery #ChargeIntegration #RAHeaders)

Fully passive dual-chain X-Band upconverter with two 5–7 GHz SMA RF inputs, a single external LO SMA passively split to two mixer chains, and dual on-board 8–10 GHz 50 Ω PCB outputs with PI-match networks, no DC-powered components, BOM <$300 #PassiveUpconverter #DualChain #XBand #NoDCPower #BOMUnder300

Two-Bank 6 V Igniter Firing System with Onboard 2S LiFePO4 Pack, S-8252A Protection, BQ24618 LiFePO4 Charger (3 A, 3.6 V Fast, <50 mA Termination, 3.8 V HPPC, 3.5 V Float), 32 SOT-223 MOSFET Outputs via MCP23017, with Reserved PCB Areas for Dual 26650 Holders, 34-pin IDC, and Barrel Jack Input #LiFePO4 #Battery #BMS

Battery-isolated 16-channel medical-grade EEG front end using dual ADS1299 analog front-ends and an STM32F405 host with integrated WiFi and microSD (SDIO), featuring corrected isolation, and robust low-jitter clock distribution for dual ADS1299 #WiFi #microSD #Isolation #Clocking #ADS1299 #STM32

Battery-Powered Audio/Bluetooth System with External TP4056 Charging, Dual MT3608 Boost Rails, and Star-Grounded Power Domains

RoboStyle Base Station Control Board – ESP32-WROOM-32, DRV8825 Stepper, Dual DIP-16 DRV8833 Actuators, High-Current Track Output, USB/Heatsink Keep-Clear, Zero-DRC Prep

230 VAC to Dual Isolated 5 V / 3.3 V DC Power Supply with Input Protection and EMI Filtering

USB-C VBUS Integration with Onboard Li-ion Charger and Power-Path for Dual Laser Drivers

Production-Ready 2-Layer ESP32-S3 Controller PCB: Dual WROOM-1U/WROOM-1 Footprints, ESD-Protected USB-C Debug, Protected 12 V Input (Fuse, Reverse Diode, TVS), TPS5430DDA Buck + TLV70033DDCT LDO Power, Integrated TMC2209 Stepper Driver, 3× 12 V/2 A LED Channels with Screw Terminals, Comprehensive Test Points, Full BOM/Pin Map/Gerbers, Logic Power Supply Audited and Validated #ESP32S3 #PowerManagement #MotorControl #LEDControl #ProductionReady #PowerAudit

Minimal USB Interconnect Board with Dual 4-pin JST XH and 2-pin VBUS/GND Breakout

Dual 6V Peristaltic Pump System with SEN0161 pH Meter Module and PH-100ATC Probe Integration

Dual K-Line & L-Line RP2040 Interface with L9613 Transceivers and JST VH Connectivity

TECHNICAL ASSIGNMENT AND DESIGN GUIDE Active Three-Way Crossover on NE5532 Powered by AM4T-4815DZ and Amplifiers TPA3255 (Updated Version) 1. GENERAL PURPOSE OF THE DEVICE The goal of the development is to create an active three-way audio crossover for one channel of a loudspeaker system, working with the following drivers: LF: VISATON W250 MF: VISATON MR130 HF: Morel MDT-12 Each frequency range is amplified by a separate power amplifier: LF: TPA3255 in PBTL mode (mono) MF + HF: second TPA3255 in stereo mode (one channel for MF, the other for HF) The crossover accepts a single linear audio signal (mono) and divides it into three frequency bands: Range Frequency Range LF 0 – 650 Hz MF 650 – 2500 Hz HF 2500 Hz and above Filter type: Linkwitz–Riley 4th order (24 dB/oct) at each crossover point (650 Hz and 2500 Hz). The crossover must provide: minimal self-noise; no audible distortion in the audible range; stable operation with NE5532 at ±15 V power supply; easy adjustment of the level for each band, as well as the overall level (via the input buffer). 2. FILTER TYPES AND BASIC OPERATING PRINCIPLES Each filter is implemented as two cascaded Sallen–Key 2nd order (Butterworth) stages, resulting in a final 4th order LR4 filter. Topology: non-inverting Sallen–Key, optimal for NE5532. For all stages: Cascade gain: K ≈ 1.586 This provides a Q factor of 0.707 (Butterworth), which in combination gives a Linkwitz–Riley 4th order. 3. COMPONENT VALUES FOR FILTERS 3.1 Universal Parameters RC chain capacitors: 10 nF, film capacitors, tolerance ≤ 5% Resistors: metal-film, tolerance ≤ 1% The gain of each stage is set by feedback resistors: Rf = 5.9 kΩ Rg = 10 kΩ K ≈ 1 + (Rf / Rg) ≈ 1.59 The circuit should allow for the installation of a small capacitor (10–47 pF) in parallel with Rf (footprint provided) for possible stability correction (not mandatory to install in the first revision). 3.2 650 Hz Filters (Low-frequency boundary for MF) These are used for the division between W250 and MR130. LP650 — Low-frequency Filter 2nd Order R1 = 24.9 kΩ R2 = 24.9 kΩ C1 = 10 nF C2 = 10 nF Two stages: LP650 #1 and LP650 #2. HP650 — MF High-frequency Filter 2nd Order Same values: R1 = 24.9 kΩ R2 = 24.9 kΩ C1 = 10 nF C2 = 10 nF Two stages: HP650 #1 and HP650 #2. 3.3 2500 Hz Filters (Upper boundary for MF) These are used for the division between MR130 → MDT-12. LP2500 — High-pass MF Filter R1 = 6.34 kΩ R2 = 6.34 kΩ C1 = 10 nF C2 = 10 nF Two stages: LP2500 #1 and LP2500 #2. HP2500 — High-frequency Filter Same values: R1 = 6.34 kΩ R2 = 6.34 kΩ C1 = 10 nF C2 = 10 nF Two stages: HP2500 #1 and HP2500 #2. 4. OPERATIONAL AMPLIFIERS The NE5532 (dual op-amp, DIP-8 or SOIC-8) is used. A minimum of 4 packages (8 channels) for filters: NE5532 Function U1A, U1B LP650 #1, LP650 #2 (LF) U2A, U2B HP650 #1, HP650 #2 (Lower MF cut-off) U3A, U3B LP2500 #1, LP2500 #2 (Upper MF cut-off) U4A, U4B HP2500 #1, HP2500 #2 (HF) Additionally: U5 — input buffer / preamplifier (both channels) If necessary, an additional NE5532 (U6) for the balanced input (see section 6.2). All NE5532 should have local decoupling for power supply (see section 5.1). 5. CROSSOVER POWER SUPPLY AM4T-4815DZ DC/DC module is used: Input: 36–72 V, connected to the 48 V power supply for TPA3255 amplifiers. Output: +15 V / –15 V, up to 0.133 A per side. Maximum output capacitance: ≤ 47 µF per side (according to the datasheet). 5.1 Power Filtering Input (48 V): RC variant (simpler, acceptable for the first revision): R = 1–2 Ω / 1–2 W C = 47–100 µF (for 63 V or higher) LC variant (preferred for improved noise immunity): L = 10–22 µH C = 47–100 µF The developer may implement LC if confident in choosing the inductance and its parameters. Output +15 V and –15 V (general filtering): Electrolytic capacitor 10–22 µF per side 100 nF (X7R) per side to GND Local decoupling for NE5532 (REQUIRED): For each NE5532 package: 100 nF between +15 V and GND 100 nF between –15 V and GND Place as close as possible to the op-amp power pins (short traces). Additional local filtering for power lines: For each NE5532, decouple from the ±15 V main rails: Either 4.7–10 Ω resistor in series with +15 V and –15 V, Or ferrite bead in each rail. After this component, place local capacitors (100 nF + 1–4.7 µF) to ground. 6. INPUT TRACT: INPUTS, BUFFER, ADJUSTMENT 6.1 Unbalanced Input (RCA / Jack / Linear) The main mode is the unbalanced linear input, for example, RCA. Input tract structure: RF-filter and protection: Signal → series resistor Rin_series = 100–220 Ω After resistor — capacitor Cin_RF = 470–1000 pF to GND This forms a low-level RF filter and reduces high-frequency noise. DC-block (low-pass HP-filter): Capacitor Cin_DC = 2.2–4.7 µF film in series Resistor to ground Rin_to_GND = 47–100 kΩ Cut-off frequency — negligible in the audio range but removes DC. Input buffer / preamplifier (NE5532, U5): Non-inverting configuration. Input — after DC-block. Gain: adjustable, e.g., Rg_fixed = 10 kΩ (to GND through trimmer) Rf = 10–20 kΩ + footprint for trimmer (e.g., 20 kΩ) The gain should be in the range of 0 dB to +10…+12 dB. Possible configuration: Rg = 10 kΩ fixed Rf = 10 kΩ + 10 kΩ trimmer in series. This allows adjusting the overall level of the crossover according to the source and amplifier levels. Buffer output: A low-impedance output (after NE5532) This signal is simultaneously fed to the inputs of all filters: LP650 (LF) HP650 → LP2500 (MF) HP2500 (HF) 6.2 Balanced Input (XLR / TRS) — Optional, but laid out on the board The board should allow for a balanced input, even if it’s not used in the first revision. Implementation requirements: XLR/TRS connector (L, R, GND) or separate 3-pin header. Simple differential receiver on NE5532 (extra U6 package or use one channel of U5 if sufficient). Circuit: classic instrumentation amplifier or differential amplifier: Inputs: IN+ and IN– Output — single-ended signal of the same level (or slightly amplified), fed to DC-block and buffer (or directly to the buffer if integrated). Switching between balanced/unbalanced mode: Implement using jumpers / bridges or adapters: Either switch before the buffer, Or use two separate pads, one of which is unused. All balanced input grounds must be connected to the same AGND point as the unbalanced input to avoid ground loops. 7. LEVEL ADJUSTMENT OF BANDS (BEST METHOD) The level adjustment of each band (LOW, MID, HIGH) is required to match the sensitivity of the speakers and amplifiers. Recommended method: After each full filter (after LP650×2, MID-chain HP650×2 → LP2500×2, HP2500×2), install: A passive attenuator: Series: Rseries (0–10 kΩ, adjustable) Shunt: Rshunt to GND (10–22 kΩ, fixed or adjustable) For simplicity and reliability: Implementation on the board: For each band (LOW, MID, HIGH) provide: Pad for multi-turn trimmer 10–20 kΩ as a divider (between signal and ground) in the "level adjustment" configuration. If adjustment is not needed — install a fixed divider (two resistors) or simply use a jumper. It is preferable to use: For setup: multi-turn trimmers 10–20 kΩ, available on the top side of the board. Nominals for the initial configuration can be selected through measurements, but the PCB should have flexibility. This provides: Accurate balancing of band volumes without interfering with the filters; Flexibility for fine-tuning to the specific characteristics of the speakers. 8. INPUTS AND OUTPUTS OF THE CROSSOVER (FINAL) 8.1 Inputs 1× Unbalanced linear input (RCA or 3-pin header) 1× Balanced input (XLR/TRS or 3-pin header) — optional, but space must be provided on the board. Input impedance (unbalanced after RF-filter): 22–50 kΩ. The input tract must be implemented using shielded cables. 8.2 Outputs Outputs to amplifiers: Output Signal LOW OUT After LP650×2 (LF) MID OUT After HP650×2 → LP2500×2 (MF) HIGH OUT After HP2500×2 (HF) Each output: Series resistor 100–220 Ω (prevents possible oscillations and simplifies cable management). A nearby own AGND pad (ground output), so the signal pair SIG+GND runs together. Outputs should be compactly placed on 2-pin connectors (SIG+GND) or 3-pin (SIG+GND+reserve). 9. PCB DESIGN REQUIREMENTS 9.1 Board Number of layers: 2 layers Bottom layer: solid analog ground (AGND). 9.2 Component Placement Key principles: RC chains of each filter (R1, R2, C1, C2, Rf, Rg) should form a compact "island" around the corresponding op-amp. If elements are placed too far apart, the filter will not work correctly (calculated frequency and Q will shift). Feedback tracks (Rf and Rg) should be as short and direct as possible. The AM4T-4815DZ module should be placed: Far from the input buffer, Far from the first filter stages, If necessary, make a "cutout" in the ground under it to limit noise propagation. Place the input connector, RF-filter, and buffer on one side of the board, and the output connectors on the opposite side. 9.3 Ground The entire audio circuit uses one analog ground: AGND. Connect AGND to the power ground (48 V and amplifiers) at one point ("star"). The star should be implemented as: One point/pad where: The ground of the input, The ground of the filters, The ground of the outputs, The ground of the DC/DC. Avoid long narrow "ground" jumpers — use wide polygons with a single connection point. 9.4 Placement of Output Connectors Group LOW/MID/HIGH compactly. Each should have its own GND pad nearby. Route the SIG+GND pairs as signal pairs, avoiding large loops. 10. ADDITIONAL ELEMENTS: PROTECTION, TEST POINTS 10.1 Test Points (TP) Be sure to provide test points (pads): TP_IN — crossover input (after buffer) TP_LOW — LF filter output TP_MID — MF filter output TP_HIGH — HF filter output TP_+15, TP_–15, TP_GND — power control This greatly simplifies debugging with an oscilloscope. 10.2 Power Protection On the 48 V input — it is advisable to provide: Diode/scheme for reverse polarity protection (if possible), TVS diode or varistor for voltage spikes (optional). 10.3 Possible Stability Correction Pads for small capacitors (10–47 pF) in parallel with Rf in buffers and, if necessary, in some stages — in case of stability issues (this can be not installed in the first revision, but footprints should be provided). 11. BILL OF MATERIALS (BOM) Operational Amplifiers: NE5532 — 4 pcs (filters) NE5532 — 1–2 pcs (input buffer and balanced input) Total: 5–6 NE5532 packages. Resistors (1%, metal-film): 24.9 kΩ — 8 pcs 6.34 kΩ — 8 pcs 10 kΩ — ≥ 12 pcs (feedback, buffers, etc.) 5.9 kΩ — 8 pcs 22 kΩ — 1–2 pcs (input, auxiliary chains) 47–100 kΩ — several pcs (DC-block, input) 100 kΩ — 1 pc (if needed) 100–220 Ω — 4–6 pcs (outputs, RF, protection) 4.7–10 Ω — 2 pcs for each op-amp or group of op-amps (power filtering) — quantity to be clarified during routing. Trimmer Resistors: 10–20 kΩ multi-turn — one for each band (LOW, MID, HIGH) 10–20 kΩ — 1–2 pcs for the input buffer (overall gain adjustment). Capacitors: 10 nF film — 16 pcs (RC filters) 2.2–4.7 µF film — 1–2 pcs (input DC-block) 10–22 µF electrolytic — 2–4 pcs (DC/DC outputs) 1–4.7 µF (X7R / tantalum) — 1 pc for local power filtering (optional). 100 nF ceramic X7R — 10–20 pcs (local decoupling for each op-amp) 470–1000 pF — 1–2 pcs (RF filter on the input) 10–47 pF — optional for stability correction (Rf). Power Supply: AM4T-4815DZ — 1 pc Inductor 10–22 µH (if LC filter) — 1 pc R 1–2 Ω / 1–2 W — 1 pc (if RC filter). Connectors: Input (RCA + 3-pin for internal input) Balanced (XLR/TRS or 3-pin header) Outputs LOW/MID/HIGH — 2-pin/3-pin connectors. 12. TESTING RECOMMENDATIONS 12.1 First Power-up Apply ±15 V without installed op-amps. Check with a multimeter: +15 V –15 V No short circuits in the power supply. Install the op-amps (NE5532). Apply a sine wave of 100–200 mV RMS (signal generator). Check with an oscilloscope at TP: LP650 — should pass LF and roll off everything above 650 Hz. HP650 — should roll off LF, pass everything above 650 Hz. LP2500 — should roll off above 2500 Hz. **HP250 0** — should pass everything above 2500 Hz. 12.2 Phase Check The Linkwitz–Riley 4th order should give a flat frequency response when summed at the crossover points. This can be verified with REW/Arta. 12.3 Noise Check If there is noticeable "shshsh" or whistling: Check: Grounding layout (star) Placement and filtering of AM4T-4815DZ Presence and proper installation of all 100 nF and local filters. 13. FINAL RECOMMENDATIONS FOR BEGINNERS Do not rush, build the circuit step by step: input → buffer → one filter → test, then continue. Check component values at least twice before soldering. Filters should be routed as compact "islands" around the op-amp, do not stretch R and C across the board. Always remember the rule: "The feedback trace should be as short as physically possible." Before ordering the PCB, make a "paper prototype": print at 1:1, cut it out, place real components to check everything fits.

Teensy 4.0 Dual CAN-FD Gateway with Switchable Bus Termination

Simplified Power Distribution Board with Single USB-C Input and Dual 5V Rails

MCU-Controlled 7-Port USB 3.0/2.0 Hub with Dual Extra USB 3.0 Downstream Ports, Per-Port 900mA Power Switches, High-Speed TVS/CMC Protection, Controlled Line Impedance (85Ω SS / 90Ω USB2), and ≥6.3A Total Current Output

ATmega328P Dual Sabertooth Motor Controller Interface with Encoder Feedback and Protected 5V Input (KiCad 9, Compact Design)

RC Tank Control Board v1: Modular 24V ESP32 Vehicle Controller (Dual H-Bridges, Stepper Support, Enhanced Safety, Ready-for-Layout)

Boiling Magenta Neuralizer: Dual Motor BLDC FOC Driver with BLE Telemetry and USB‑C PD Input

Compact LoRa-based load cell manager board. Hosts Heltec WiFi LoRa 32, HX711 ADC for strain gauges, dual VL53L1X ToF sensors, 3.3V/2.8V rails, user buttons/LEDs, and screw terminals for robust interfacing.

This is a reference design for TJA1059TKJ Dual high-speed CAN transceiver with Standby mode. It offers advanced features, such as wake-up capability and high-speed data rates, making it suitable for automotive and industrial applications. #MCP25612FD #CANbus #transceiver #highspeed #automotive #referenceDesign #project #CANbus #interface #transceiverCircuit #TJA1059TKJ #referenceDesign #canbus #nxp #template #reference-design

Dual core, Wi-Fi: 2.4 GHz up to 150 Mbits/s,BLE (Bluetooth Low Energy) and legacy Bluetooth, 32 bits, Up to 240 MHz #esp32 #ble #wifi #arm

In this project a +18V and a -18V dual power supply is implemented.

Dual core, Wi-Fi: 2.4 GHz up to 150 Mbits/s,BLE (Bluetooth Low Energy) and legacy Bluetooth, 32 bits, Up to 240 MHz #esp32 #ble #wifi #arm

This is a reference design for TJA1059TKJ Dual high-speed CAN transceiver with Standby mode. It offers advanced features, such as wake-up capability and high-speed data rates, making it suitable for automotive and industrial applications. #MCP25612FD #CANbus #transceiver #highspeed #automotive #referenceDesign #project #CANbus #interface #transceiverCircuit #TJA1059TKJ #referenceDesign #canbus #nxp #template #reference-design

This project is a dual channel SPH0645LM4H-B microphone controlled by ESP32 Template #audioDevices #audio #esp32 #recorder #SPH0645LM4H-B #referenceDesign

This project involves designing a complete schematic for a robotic arm controller based on the ESP32-C3 microcontroller, specifically using the ESP32-C3-MINI-1-N4 module. The design features a dual power input system and comprehensive power management, motor control, I/O interfaces, and status indicators—all implemented on a 2-layer PCB. Key Specifications: Microcontroller: • ESP32-C3-MINI-1-N4 module operating at 3.3V. • Integrated USB programming connections with reset and boot mode buttons. Power System: • Dual power inputs with automatic source selection: USB-C port (5V input) and barrel jack (6-12V input). • Power management using LM74610 smart diode controllers for power source OR-ing. • AMS1117-3.3 voltage regulator to deliver a stable 3.3V supply to the microcontroller. • Filter capacitors (10μF electrolytic and 100nF ceramic) at the input and output of the regulators. • Protection features including USBLC6-2SC6 for USB ESD protection and TVS diodes for barrel jack overvoltage protection. Motor Control: • Incorporates an Omron G5LE relay with a PC817 optocoupler and BC547 transistor driver. • Provides dedicated header pins for servo motors with PWM outputs. • Flyback diode protection implemented for relay safety. I/O Connections: • Header pins exposing ESP32-C3 GPIOs: Digital I/O (IO0-IO10, IO18, IO19) and serial communication lines (TXD0, RXD0), plus an enable pin. • Each I/O pin includes appropriate 10kΩ pull-up/pull-down resistors to ensure reliable performance. Status Indicators: • A power status LED with a current-limiting resistor. • A user-controllable LED connected to one of the GPIO pins. PCB Layout Requirements: • 2-layer PCB design with separate ground planes for digital and power sections. • Placement of decoupling capacitors close to power pins to reduce noise. • Adequate trace width for power lines to ensure efficient current flow. • Inclusion of mounting holes at the board corners for secure installation. • All components are properly labeled with correct values for resistors, capacitors, and other passive elements, following standard design practices for noise reduction, stability, and reliability. #RoboticArmController #ESP32C3 #SchematicDesign #PCBDesign #ElectronicsDesign #PowerManagement #MotorControl #EmbeddedSystems #IoT

Dual core, Wi-Fi: 2.4 GHz up to 150 Mbits/s,BLE (Bluetooth Low Energy) and legacy Bluetooth, 32 bits, Up to 240 MHz #esp32 #ble #wifi #arm