The 223P Adjustable Variable Tuning Capacitor (40pF–180pF) is a precision miniature poly-dielectric variable capacitor (polyvaricon) designed for manual frequency tuning in AM/FM radio receivers, regenerative tuners, crystal radios, and RF test oscillators. Featuring independent stator and rotor sections insulated by low-loss plastic dielectric films, this tuning capacitor delivers smooth continuous capacitance adjustment, integrated back-side trimmer screws for fine-tuning, and low RF insertion loss in a compact through-hole enclosure.

Specifications

• Model / Part Number: 223P / CBM-223P Series
• Product Type: Poly-Dielectric Variable Gang Tuning Capacitor (Polyvaricon)
• Main Tuning Capacitance Range (AM Section): Approx. 40pF to 180pF (or 60pF to 140pF depending on gang wiring)
• FM Section Capacitance (if dual-gang): Approx. 5pF to 20pF
• Integrated Trimmer Capacitance: Approx. 2pF to 8pF (Adjustable via rear trimmer screws)
• Dielectric Material: High-Grade Low-Loss Polyethylene / Polyester Film
• Rated Voltage: 100V DC Max
• Insulation Resistance: ≥ 100MΩ (at 100V DC)
• Rotational Angle: 180° Full Travel (Smooth Continuous Rotation)
• Torque Range: 50 to 400 gf·cm (Provides firm tuning feel without slippage)
• Shaft / Spindle: M2.5 threaded center shaft (Fits standard radio tuning dials and pointer knobs)
• Mounting / Termination: Standard 3-Pin / 4-Pin Through-Hole PCB solder pins
• Operating Temperature: -10°C to +60°C
• Dimensions: Approx. 21mm x 21mm x 12mm (excluding shaft and pins)

Features

• Smooth 180-Degree Tuning: Provides linear, smooth capacitance variation over a full 180° rotation for stable station selection.
• Built-in Rear Trimmers: Integrated ceramic trimmer capacitors on the rear plate allow fine frequency calibration and tracking adjustment without external trimmers.
• Low RF Loss: High-quality polymer dielectric films ensure high Q-factor and low signal loss in resonant RF tank circuits.
• Standard M2.5 Dial Mount: Center threaded shaft accommodates standard tuning knobs, vernier reduction dials, and pointer mechanisms.
• Compact & Enclosed: Sealed plastic housing protects internal plates from dust, moisture, and accidental physical bending.

Common Applications

• AM / MW Radio Receivers: Main LC tank tuning capacitor for superheterodyne, TRF, and regenerative AM receivers.
• DIY Crystal Radio Sets: High-Q variable tuning element for passive crystal radio detectors and antenna tuners.
• Shortwave (SW) & Amateur Radio Tuners: Resonant tank selection in DIY shortwave receivers and QRP preselectors.
• RF Signal Generators & VFOs: Variable frequency oscillators, beat frequency oscillators (BFO), and RF grid-dip meters.
• Antenna Matching Units (ATU): Small loop antenna and wire antenna impedance tuning for low-power communications.

Usage Tips

• Pinout & Gang Wiring: The common rotor connection is usually tied to the center pin and the front metal shaft (circuit ground). Connect the outer stator pins to your tuned inductor coil.
• Mounting Screws Caution: When securing the capacitor to a panel or bracket with M2.5 screws, make sure the screw depth does not exceed 2.0mm–2.5mm inside the casing to avoid penetrating and shorting the internal rotor plates.
• Tuning Alignment: Use an insulated non-metallic alignment screwdriver to adjust the small rear trimmer screws when fine-tuning tracking at the high-frequency end of the radio dial.
• Hand-Capacitance Shielding: Connect the common rotor terminal (which connects to the shaft) to circuit ground or 0V to minimize hand-capacitance frequency detuning while turning the knob.

Datasheet