The **P-34N-R** is a specific model of an analog panel meter, typically used to measure audio signals (VU levels) or electrical parameters in industrial and consumer electronics. Below is a detailed breakdown of its electronic parts and specifications. --- ## 1. Physical and Electronic Components The P-34N-R consists of several integrated parts that work together to provide a visual representation of signal levels. | Component | Description | Function | | :--- | :--- | :--- | | **D'Arsonval Movement** | A core coil suspended between permanent magnets. | Converts electrical current into physical needle movement. | | **Scale Plate** | A printed background (usually -20 to +3 VU). | Provides the reference for the measurement. | | **Lamp/Backlight** | Often a 12V or 6.3V LED or incandescent bulb. | Allows for visibility in low-light environments. | | **Rectifier (Internal)** | Diodes (often Germanium for low voltage drop). | Converts AC audio signals into DC for the movement. | | **Zero-Adjust Screw** | A mechanical screw located at the bottom center. | Calibrates the needle to the zero (rest) position. | --- ## 2. Technical Specifications While specifications can vary slightly by manufacturer (such as NISSEI), the standard electronic characteristics for the P-34 series are: * **Sensitivity:** Usually $500\mu A$ (Microamps) for full-scale deflection. * **Internal Impedance:** Approximately $650 \Omega \pm 10\%$. * **Light Source:** DC/AC 6V-12V (LED versions are common in newer "R" models). * **Operating Temperature:** $-10^\circ C$ to $+60^\circ C$. --- ## 3. Circuit Wiring Overview To use a P-34N-R as a volume unit (VU) meter in an audio circuit, a driver board is typically required to protect the delicate coil. ```mermaid graph LR A[Audio Signal] --> B[Driver Board/Resistor] B --> C[P-34N-R Meter] D[Power Supply 12V] --> E[Backlight Pins] ``` ### Connection Pins 1. **Meter Terminals (+/-):** These receive the DC current from the driver board. **Caution:** Direct connection to high-wattage speaker outputs can burn the internal coil. 2. **Lamp Terminals:** Separate pins used to power the illumination. --- ## 4. Key Applications * **Audio Mixers:** Monitoring output levels to prevent clipping. * **Amplifiers:** Adding a vintage "Retro" aesthetic to DIY tube amps. * **Radio Equipment:** Measuring SWR (Standing Wave Ratio) or signal strength.