# Remote Lime Heat-Ray ## Description CT (0-5A AC) to 0-3.3V DC galvanically-isolated signal conditioner ## Project Details - **Owner:** dominant741 - **Created:** 3/8/2026 - **Last Updated:** 3/8/2026 - **Visibility:** Public - **System Architecture:** ```mermaid flowchart TD subgraph PrimaryDomain [Primary domain - CT side] J1["J1 CT input"] --> RB["R_BURDEN shunt"] --> Rect["U1 precision full-wave rectifier"] --> F1["RC filter stage 1"] --> F2["RC filter stage 2"] --> U2["U2 TL071 LED driver"] end subgraph IsolationBarrier [Isolation barrier] U3["U3 HCNR201 analog optocoupler"] UDC["U_DCDC B0505S isolated DC-DC"] end subgraph SecondaryDomain [Secondary domain - MCU side] TIA["U4 MCP6001 transimpedance"] --> GAIN["U5 MCP6001 gain 1.65"] --> CLAMP["Zener clamp + RC"] --> J2["J2 ADC output"] end J3["J3 5V input"] --> PRI["+5V_PRI"] PRI --> PrimaryDomain PRI --> UDC UDC --> ISO["+5V_ISO"] ISO --> SecondaryDomain U2 -->|LED drive| U3 U3 -->|PD2 current| TIA GND1["GND1"] --> PrimaryDomain GND1 --> UDC GND2["GND2"] --> SecondaryDomain GND2 --> UDC ``` ## Key Components ### D1 — [1N4148](https://www.flux.ai/lcsc/1n4148.md) - Package: DO-35 - JLCPCB Part Class: Extended Part - Product Info Url: https://lcsc.com/product-detail/Switching-Diode_ON-Semicon_1N4148_ON-Semicon-ON-1N4148_C258182.html - Role: Diode - Manufacturer Name: onsemi(安森美) - Manufacturer Part Number: 1N4148 - Package or Case Code: DO-35_BD2.0-L4.0-P8.00-D0.5-FD - Role Details: Precision rectifier steering diode 1 - Part Type: Switching Diode - Datasheet URL: https://lcsc.com/product-detail/Switching-Diode_ON-Semicon_1N4148_ON-Semicon-ON-1N4148_C258182.html - LCSC Part Number: C258182 **Pins:** - A [pin 1] - K [pin 2] ### D2 — [1N4148](https://www.flux.ai/lcsc/1n4148.md) - Package: DO-35 - JLCPCB Part Class: Extended Part - Product Info Url: https://lcsc.com/product-detail/Switching-Diode_ON-Semicon_1N4148_ON-Semicon-ON-1N4148_C258182.html - Manufacturer Name: onsemi(安森美) - Manufacturer Part Number: 1N4148 - Package or Case Code: DO-35_BD2.0-L4.0-P8.00-D0.5-FD - Part Type: Switching Diode - Role: Diode - Role Details: Precision rectifier steering diode 2 - Datasheet URL: https://lcsc.com/product-detail/Switching-Diode_ON-Semicon_1N4148_ON-Semicon-ON-1N4148_C258182.html - LCSC Part Number: C258182 **Pins:** - A [pin 1] - K [pin 2] ### D3 — [BZX55C3V3](https://www.flux.ai/lcsc/bzx55c3v3.md) - LCSC Part Number: C3041345 - Manufacturer Name: ST(先科) - Manufacturer Part Number: BZX55C3V3 - Role: Clamp - Role Details: 3.3V zener clamp on ADC output - Package: DO-35 - JLCPCB Part Class: Extended Part - Package or Case Code: DO-35_BD2.0-L4.2-P8.20-D0.5-RD - Part Type: Zener Diodes **Pins:** - 1 [pin 1] - 2 [pin 2] ### J1 — [1729128](https://www.flux.ai/jecstronic/1729128.md) - Datasheet URL: https://www.phoenixcontact.com/us/products/1729128/pdf - Manufacturer Part Number: 1729128 - License: https://creativecommons.org/licenses/by/4.0/ - Role: Connector - Manufacturer Name: Phoenix Contact - Role Details: CT input 0-5A AC - Part Type: Connector - Package: THT 2P 5.08mm **Pins:** - PIN1 [pin 1] - PIN2 [pin 2] ### J2 — [1729128](https://www.flux.ai/jecstronic/1729128.md) - Datasheet URL: https://www.phoenixcontact.com/us/products/1729128/pdf - Role Details: ADC output 0-3.3V DC and GND2 - Package: THT 2P 5.08mm - Manufacturer Name: Phoenix Contact - Role: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: 1729128 - Part Type: Connector **Pins:** - PIN1 [pin 1] - PIN2 [pin 2] ### J3 — [1729128](https://www.flux.ai/jecstronic/1729128.md) - Part Type: Connector - Role Details: +5V input (primary) - Package: THT 2P 5.08mm - Role: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: 1729128 - Manufacturer Name: Phoenix Contact - Datasheet URL: https://www.phoenixcontact.com/us/products/1729128/pdf **Pins:** - PIN1 [pin 1] - PIN2 [pin 2] ### Rf — [Generic Resistor](https://www.flux.ai/jharwinbarrozo/generic-resistor.md) - Role: Gain set - Package: SMD_0805_2012Metric - Resistance: 6.8kΩohms - Part Type: Resistor - Role Details: Gain stage feedback resistor (with trim pot) **Pins:** - P1 [pin 1] - P2 [pin 2] ### Rg — [Generic Resistor](https://www.flux.ai/jharwinbarrozo/generic-resistor.md) - Package: SMD_0805_2012Metric - Role: Gain set - Resistance: 10kΩohms - Role Details: Gain stage resistor to GND2 - Part Type: Resistor **Pins:** - P1 [pin 1] - P2 [pin 2] ### Rs — [Generic Resistor](https://www.flux.ai/jharwinbarrozo/generic-resistor.md) - Resistance: 100Ωohms - Part Type: Resistor - Role: Protection - Role Details: Series resistor into ADC output node - Package: SMD_0805_2012Metric **Pins:** - P1 [pin 1] - P2 [pin 2] ### RV1 — [3299W-1-103](https://www.flux.ai/jecstronic/3299w-1-103.md) - Package: THT Trimmer - Role: Trim - Part Type: Potentiometer - Manufacturer Part Number: 3299W-1-103 - Datasheet URL: https://www.bourns.com/docs/Product-Datasheets/3299.pdf - Manufacturer Name: Bourns Inc. - Role Details: Multi-turn trimmer in feedback (library has 10k; will adjust circuit to use 10k or replace when 5k available) - License: https://creativecommons.org/licenses/by/4.0/ - Resistance: 10kΩ **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### RV1 — [3296W-1-502](https://www.flux.ai/lcsc/3296w-1-502.md) - Role: Trim - Package or Case Code: RES-ADJ-TH_3P-L9.5-W4.85-P2.50-BL-BS - LCSC Part Number: C118907 - Part Type: Variable Resistors/Potentiometers - Tolerance: ±10% - Manufacturer Name: BOCHEN(博晨) - Role Details: 5k multi-turn style footprint for gain trim in feedback - Manufacturer Part Number: 3296W-1-502 - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/1811011704_BOCHEN-Chengdu-Guosheng-Tech-3296W-1-502_C118907.pdf - JLCPCB Part Class: Extended Part - Product Info Url: https://lcsc.com/product-detail/Precision-Potentiometer_5KR_C118907.html - Power Rating: 0.5W - Resistor Type: Variable - Package: THT Trimmer - Resistance: 5kΩ **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### TP1 — [5014](https://www.flux.ai/adrian95/5014.md) - Package: THT Testpoint - Manufacturer Part Number: 5014 - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: TP1 burden resistor output (AC) - Role: Testpoint - Datasheet URL: https://www.keyelco.com/userAssets/file/M65p56.pdf - Manufacturer Name: Keystone Electronics - Part Type: Connector **Pins:** - 1 [pin 1] ### TP2 — [5014](https://www.flux.ai/adrian95/5014.md) - License: https://creativecommons.org/licenses/by/4.0/ - Role: Testpoint - Manufacturer Part Number: 5014 - Role Details: TP2 post-rectifier pulsed DC - Package: THT Testpoint - Manufacturer Name: Keystone Electronics - Part Type: Connector - Datasheet URL: https://www.keyelco.com/userAssets/file/M65p56.pdf **Pins:** - 1 [pin 1] ### TP3 — [5014](https://www.flux.ai/adrian95/5014.md) - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: 5014 - Role Details: TP3 post-filter smooth DC - Role: Testpoint - Manufacturer Name: Keystone Electronics - Package: THT Testpoint - Part Type: Connector - Datasheet URL: https://www.keyelco.com/userAssets/file/M65p56.pdf **Pins:** - 1 [pin 1] ### TP4 — [5014](https://www.flux.ai/adrian95/5014.md) - License: https://creativecommons.org/licenses/by/4.0/ - Package: THT Testpoint - Role Details: TP4 isolated side after optocoupler - Role: Testpoint - Manufacturer Part Number: 5014 - Part Type: Connector - Manufacturer Name: Keystone Electronics - Datasheet URL: https://www.keyelco.com/userAssets/file/M65p56.pdf **Pins:** - 1 [pin 1] ### TP5 — [5014](https://www.flux.ai/adrian95/5014.md) - License: https://creativecommons.org/licenses/by/4.0/ - Package: THT Testpoint - Role Details: TP5 final output before J2 - Manufacturer Part Number: 5014 - Part Type: Connector - Manufacturer Name: Keystone Electronics - Role: Testpoint - Datasheet URL: https://www.keyelco.com/userAssets/file/M65p56.pdf **Pins:** - 1 [pin 1] ### U_DCDC — [CRE1S0505SC](https://www.flux.ai/kicad-part-library/cre1s0505sc.md) - Package or Case Code: Converter_DCDC_Murata_CRE1xxxxxxSC_THT - Manufacturer Name: Texas Instruments Inc. - Role: Isolated DC-DC - Datasheet URL: http://power.murata.com/datasheet?/data/power/ncl/kdc_cre1.pdf - Manufacturer Part Number: CRE1S0505SC - Role Details: 5V_PRI to 5V_ISO isolated supply (1W class) - Package: SIP-4 - Part Type: Converter DCDC **Pins:** - -VIN [pin 1] - -VOUT [pin 3] - +VIN [pin 2] - +VOUT [pin 4] ### U1 — [LM358P](https://www.flux.ai/jecstronic/lm358p.md) - Manufacturer Name: Texas Instruments - Role: OpAmp - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://www.ti.com/general/docs/suppproductinfo.tsp?distId=10&gotoUrl=https%3A%2F%2Fwww.ti.com%2Flit%2Fgpn%2Flm358 - Package: PDIP-8 - Manufacturer Part Number: LM358P - Part Type: Operational Amplifier (OP-AMP) - Role Details: Precision full-wave rectifier (dual) on CT side **Pins:** - -IN1 [pin 2] - -IN2 [pin 6] - +IN1 [pin 3] - +IN2 [pin 5] - OUT1 [pin 1] - OUT2 [pin 7] - V- [pin 4] - V+ [pin 8] ### U2 — [LM358P](https://www.flux.ai/jecstronic/lm358p.md) - Package: PDIP-8 - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: Texas Instruments - Datasheet URL: https://www.ti.com/general/docs/suppproductinfo.tsp?distId=10&gotoUrl=https%3A%2F%2Fwww.ti.com%2Flit%2Fgpn%2Flm358 - Part Type: Operational Amplifier (OP-AMP) - Role: OpAmp - Manufacturer Part Number: LM358P - Role Details: Replaces TL071CP for 5V single-supply compatibility; drives HCNR LED with PD1 feedback using one channel **Pins:** - -IN1 [pin 2] - -IN2 [pin 6] - +IN1 [pin 3] - +IN2 [pin 5] - OUT1 [pin 1] - OUT2 [pin 7] - V- [pin 4] - V+ [pin 8] ### U3 — [HCNR200-000E](https://www.flux.ai/lcsc/hcnr200-000e.md) - Package or Case Code: DIP-8_L9.3-W6.4-P2.54-LS10.9-BL - Role: Analog Isolation - JLCPCB Part Class: Extended Part - Part Type: Optocouplers - Phototransistor Output - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2204131730_Broadcom-AVAGO-HCNR200-000E_C160595.pdf - LCSC Part Number: C160595 - Product Info Url: https://lcsc.com/product-detail/DIP-Optocouplers_AVAGO_HCNR200-000E_HCNR200-000E_C160595.html - Package: DIP-8 - Manufacturer Part Number: HCNR200-000E - Role Details: Linear optocoupler across isolation slot (HCNR201 DIP-8 not in library; using HCNR200 DIP-8 as closest) - Manufacturer Name: Broadcom/AVAGO(安华高) **Pins:** - LAN [pin 2] - LCAT [pin 1] - NC [pin 8] - NC [pin 7] - PD1AN [pin 4] - PD1CAT [pin 3] - PD2AN [pin 5] - PD2CAT [pin 6] ### U4 — [MCP6002-I/P](https://www.flux.ai/adrian95/mcp6002-ip.md) - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: Microchip - Package: PDIP-8 - Part Type: Operational Amplifier (OP-AMP) - Package or Case Code: DIP781W56P254L950H533Q8N - Datasheet URL: https://ww1.microchip.com/downloads/en/DeviceDoc/MCP6001-1R-1U-2-4-1-MHz-Low-Power-Op-Amp-DS20001733L.pdf - Manufacturer Part Number: MCP6002-I/P - Role: OpAmp - Role Details: ChA=TIA for PD2, ChB=gain stage ~1.65 on isolated side **Pins:** - VDD [pin 8] - VINA- [pin 2] - VINA+ [pin 3] - VINB- [pin 6] - VINB+ [pin 5] - VOUTA [pin 1] - VOUTB [pin 7] - VSS [pin 4] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/dominant741/remote-lime-heat-ray](https://www.flux.ai/dominant741/remote-lime-heat-ray).* --- *Generated from [https://www.flux.ai/dominant741/remote-lime-heat-ray](https://www.flux.ai/dominant741/remote-lime-heat-ray)*