Chat

Welcome to Flux

Treat Flux like your intern. Tell it what you'd like to build and it'll get to work. You can also ask it questions, brainstorm ideas, and teach it your preferences. Learn More

Explain project
Write a project description
Find schematic issues
Create a test plan
Simulate a circuit
Prepare for Manufacturing
Component Selection Workflow
New Subsystem Wizard

Ready.

Sign up to send
I want to create a transimpedance amplifier with a very high gain using LM358 to...
kevinthomasajax

kevinthomasajax

@copilot I want to create a transimpedance amplifier with a very high gain using LM358 to take the output from an IR photodiode and make it readable by an ESP32
1y

copilot

Creating a transimpedance amplifier (TIA) with the LM358 op-amp to amplify the current from an IR photodiode (BPW34) and feed a readable voltage level to an ESP32 is a common approach for photo-detection projects. For a high gain, the feedback resistor value needs to be high. However, since you're aiming for "very high gain," it’s crucial to manage noise and stability. Here is how you can connect the components:
  • Transimpedance Amplifier Design:
    • Use the BPW34 as your photodiode. For an optimal response, connect it in reverse bias. This configuration improves the speed and increases the responsivity due to the wider depletion region.
    • The LM358, a dual op-amp, will be used here in a single-supply operation suitable for your ESP32's logic levels. Use only one amplifier per LM358 for this purpose.
Suggested Circuit Connections
  1. Photodiode (CELL1) to Op-Amp (U2):
    • Connect CELL1:2 (Anode) to U2:3 (+IN1).
    • Connect CELL1:1 (Cathode) to U2:2 (-IN1) and also to one end of the feedback resistance (R1).
    • You might also need to connect the anode of the photodiode to the positive supply through a high-value resistor (let's assume R2 for discussion, not included in your current project list) to ensure reverse bias and improve the response. The value of R2 could be in the range of $10 \text{k}\Omega$ to $100 \text{k}\Omega$.
    • The feedback resistor (R1) should be connected between U2:1 (OUT1) and U2:2 (-IN1). Given your high gain requirement, start with $1 \text{M}\Omega$ (R1's value might need to be adjusted based on your exact gain requirements and noise performance).
  2. Supply Voltage for LM358 (U2):
    • Connect U2:4 (V-) to U1:2 (GND).
    • Connect U2:8 (V+) to U1:1 (3V3).
  3. Output to ESP32:
    • Connect U2:1 (OUT1) to one of the ADC pins of the ESP32 for reading the voltage level. Assuming you choose pin D32 for the ADC input, connect U2:1 to U1:21 (D32).
  4. Decoupling Capacitor for Noise Reduction (optional but recommended):
    • Place a capacitor (C1) close to the LM358’s power supply pins for noise reduction. A value of $100 \text{nF}$ is typically used. So, connect C1 across U2:4 (V-) and U2:8 (V+).
  5. Output to LED (optional, for visual indication):
    • If you want a visual indication, you can use LED1 as an output indicator. This would require a current-limiting resistor (not listed in your project components). The connection would then be from U2:1 (OUT1) through a resistor to LED1:2 (A), and LED1:1 (K) to U1:2 (GND).
Please Note:
  • The actual gain of your TIA will depend on the feedback resistor (R1). You may need to adjust the value based on your sensitivity requirements and the input signal from the photodiode.
  • It's crucial to keep the layout tight, especially around the high-gain sections, to minimize noise pick-up.
  • Since a very high gain is mentioned but not quantified, I opted for a 1 MΩ feedback resistor as a starting point. Adjust based on experimental feedback and noise considerations.
Assumptions:
  • You will power the LM358 from the ESP32's 3.3V supply to keep things simple and compatible.
  • An ADC pin (D32) on the ESP32 is used for reading the amplified signal.
Feel free to adjust the values based on your testing and the specific requirements you have.
1y
5
R1
Resistance
500 Ω
CELL1
C1
Capacitance
Capacitance
U2
U3
LED1
U1
  • Ground
    Ground
    A common return path for electric current. Commonly known as ground.
    jharwinbarrozo
    20.5M
  • Net Portal
    Net Portal
    Wirelessly connects nets on schematic. Used to organize schematics and separate functional blocks. To wirelessly connect net portals, give them same designator. #portal
    jharwinbarrozo
    43.0M
  • Power Net Portal
    Power Net Portal
    Wirelessly connects power nets on schematic. Identical to the net portal, but with a power symbol. Used to organize schematics and separate functional blocks. To wirelessly connect power net portals, give them the same designator. #portal #power
    jharwinbarrozo
    11.4M
  • Generic Resistor
    Generic Resistor
    A generic fixed resistor for rapid developing circuit topology. Save precious design time by seamlessly add more information to this part (value, footprint, etc.) as it becomes available. Standard resistor values: 1.0Ω 10Ω 100Ω 1.0kΩ 10kΩ 100kΩ 1.0MΩ 1.1Ω 11Ω 110Ω 1.1kΩ 11kΩ 110kΩ 1.1MΩ 1.2Ω 12Ω 120Ω 1.2kΩ 12kΩ 120kΩ 1.2MΩ 1.3Ω 13Ω 130Ω 1.3kΩ 13kΩ 130kΩ 1.3MΩ 1.5Ω 15Ω 150Ω 1.5kΩ 15kΩ 150kΩ 1.5MΩ 1.6Ω 16Ω 160Ω 1.6kΩ 16kΩ 160kΩ 1.6MΩ 1.8Ω 18Ω 180Ω 1.8KΩ 18kΩ 180kΩ 1.8MΩ 2.0Ω 20Ω 200Ω 2.0kΩ 20kΩ 200kΩ 2.0MΩ 2.2Ω 22Ω 220Ω 2.2kΩ 22kΩ 220kΩ 2.2MΩ 2.4Ω 24Ω 240Ω 2.4kΩ 24kΩ 240kΩ 2.4MΩ 2.7Ω 27Ω 270Ω 2.7kΩ 27kΩ 270kΩ 2.7MΩ 3.0Ω 30Ω 300Ω 3.0KΩ 30KΩ 300KΩ 3.0MΩ 3.3Ω 33Ω 330Ω 3.3kΩ 33kΩ 330kΩ 3.3MΩ 3.6Ω 36Ω 360Ω 3.6kΩ 36kΩ 360kΩ 3.6MΩ 3.9Ω 39Ω 390Ω 3.9kΩ 39kΩ 390kΩ 3.9MΩ 4.3Ω 43Ω 430Ω 4.3kΩ 43KΩ 430KΩ 4.3MΩ 4.7Ω 47Ω 470Ω 4.7kΩ 47kΩ 470kΩ 4.7MΩ 5.1Ω 51Ω 510Ω 5.1kΩ 51kΩ 510kΩ 5.1MΩ 5.6Ω 56Ω 560Ω 5.6kΩ 56kΩ 560kΩ 5.6MΩ 6.2Ω 62Ω 620Ω 6.2kΩ 62KΩ 620KΩ 6.2MΩ 6.8Ω 68Ω 680Ω 6.8kΩ 68kΩ 680kΩ 6.8MΩ 7.5Ω 75Ω 750Ω 7.5kΩ 75kΩ 750kΩ 7.5MΩ 8.2Ω 82Ω 820Ω 8.2kΩ 82kΩ 820kΩ 8.2MΩ 9.1Ω 91Ω 910Ω 9.1kΩ 91kΩ 910kΩ 9.1MΩ #generics #CommonPartsLibrary
    jharwinbarrozo
    1.5M
  • Generic Capacitor
    Generic Capacitor
    A generic fixed capacitor ideal for rapid circuit topology development. You can choose between polarized and non-polarized types, its symbol and the footprint will automatically adapt based on your selection. Supported options include standard SMD sizes for ceramic capacitors (e.g., 0402, 0603, 0805), SMD sizes for aluminum electrolytic capacitors, and through-hole footprints for polarized capacitors. Save precious design time by seamlessly add more information to this part (value, footprint, etc.) as it becomes available. Standard capacitor values: 1.0pF 10pF 100pF 1000pF 0.01uF 0.1uF 1.0uF 10uF 100uF 1000uF 10,000uF 1.1pF 11pF 110pF 1100pF 1.2pF 12pF 120pF 1200pF 1.3pF 13pF 130pF 1300pF 1.5pF 15pF 150pF 1500pF 0.015uF 0.15uF 1.5uF 15uF 150uF 1500uF 1.6pF 16pF 160pF 1600pF 1.8pF 18pF 180pF 1800pF 2.0pF 20pF 200pF 2000pF 2.2pF 22pF 20pF 2200pF 0.022uF 0.22uF 2.2uF 22uF 220uF 2200uF 2.4pF 24pF 240pF 2400pF 2.7pF 27pF 270pF 2700pF 3.0pF 30pF 300pF 3000pF 3.3pF 33pF 330pF 3300pF 0.033uF 0.33uF 3.3uF 33uF 330uF 3300uF 3.6pF 36pF 360pF 3600pF 3.9pF 39pF 390pF 3900pF 4.3pF 43pF 430pF 4300pF 4.7pF 47pF 470pF 4700pF 0.047uF 0.47uF 4.7uF 47uF 470uF 4700uF 5.1pF 51pF 510pF 5100pF 5.6pF 56pF 560pF 5600pF 6.2pF 62pF 620pF 6200pF 6.8pF 68pF 680pF 6800pF 0.068uF 0.68uF 6.8uF 68uF 680uF 6800uF 7.5pF 75pF 750pF 7500pF 8.2pF 82pF 820pF 8200pF 9.1pF 91pF 910pF 9100pF #generics #CommonPartsLibrary
    jharwinbarrozo
    1.5M
  • Generic Inductor
    Generic Inductor
    A generic fixed inductor for rapid developing circuit topology. *You can now change the footprint and 3D model at the top level anytime you want. This is the power of #generics
    jharwinbarrozo
    15.5k
  • Terminal
    Terminal
    An electrical connector acting as reusable interface to a conductor and creating a point where external circuits can be connected.
    natarius
  • RMCF0805JT47K0
    RMCF0805JT47K0
    47 kOhms ±5% 0.125W, 1/8W Chip Resistor 0805 (2012 Metric) Automotive AEC-Q200 Thick Film #forLedBlink
    jharwinbarrozo
    1.2M
  • 875105359001
    875105359001
    10uF Capacitor Aluminum Polymer 20% 16V SMD 5x5.3mm #forLedBlink #commonpartslibrary #capacitor #aluminumpolymer #radialcan
    jharwinbarrozo
    1.2M
  • CTL1206FYW1T
    CTL1206FYW1T
    Yellow 595nm LED Indication - Discrete 1.7V 1206 (3216 Metric) #forLedBlink
    jharwinbarrozo
    1.1M
MINI PROJECT thumbnail
Welcome to your new project. Imagine what you can build here.

Properties

Properties describe core aspects of the project.

Pricing & Availability

Distributor

Qty 1

Assets

No assets added.

Controls