INDUSTRY COMPONENT

Hold Capacitor

A capacitor in a sample-and-hold circuit that stores and maintains the sampled analog voltage signal for a defined period.

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Component Specifications

Definition
A hold capacitor is a critical passive electronic component within a sample-and-hold (S/H) circuit. Its primary function is to acquire and store an analog voltage sample from the input signal during the 'sample' phase when the sampling switch is closed. During the subsequent 'hold' phase, when the switch opens, the capacitor must maintain this stored charge with minimal leakage or droop, providing a stable voltage to the output buffer or analog-to-digital converter (ADC) for processing. Its performance directly impacts the circuit's accuracy, speed, and signal integrity.
Working Principle
The hold capacitor operates on the fundamental principle of electrostatic energy storage. During the sample phase, it charges to the instantaneous voltage of the input signal. During the hold phase, it ideally retains this charge due to its high insulation resistance, creating a stable output voltage. The capacitor's value, dielectric material, and physical construction determine key parameters like acquisition time, droop rate, and dielectric absorption.
Materials
Dielectric: Typically polypropylene, polystyrene, or Teflon (PTFE) for low leakage, low dielectric absorption, and high stability. Electrodes: Metalized film or foil (e.g., aluminum). Encapsulation: Epoxy resin or plastic case. Leads: Tin-plated copper.
Technical Parameters
  • Tolerance ±1% to ±5%
  • Capacitance 100pF to 10nF (typical range)
  • Voltage Rating 50V to 200V
  • Leakage Current <1nA
  • Dielectric Absorption <0.01% to 0.1%
  • Operating Temperature -55°C to +125°C
  • Temperature Coefficient ±50ppm/°C to ±100ppm/°C
Standards
IEC 60384, MIL-PRF-123

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for Hold Capacitor.

hold capacitor sample-and-hold circuit S/H capacitor analog signal storage charge retention dielectric absorption polypropylene capacitor precision capacitor ADC interface signal integrity Hold Capacitor in Computer, Electronic and Optical Product Manufacturing

Parent Products

This component is used in the following industrial products

Sample-and-Hold (S/H) Circuit

An electronic circuit that samples an analog signal at a specific instant and holds that value constant for subsequent processing.

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Sample-and-Hold Circuit

An electronic circuit that captures and holds an analog voltage signal at a specific instant in time for subsequent processing.

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Engineering Analysis

Risks & Mitigation
  • Dielectric absorption causing signal error
  • Leakage current leading to voltage droop
  • Temperature drift affecting stability
  • Parasitic inductance/capacitance limiting high-frequency performance
FMEA Triads
Trigger: Dielectric degradation or contamination
Failure: Increased leakage current and dielectric absorption
Mitigation: Use high-quality, stable dielectric materials (e.g., polypropylene); implement rigorous incoming quality control; design with guard rings or low-leakage op-amps.
Trigger: Poor solder joint or mechanical stress
Failure: Intermittent connection or capacitance shift
Mitigation: Follow proper soldering profiles; use strain relief on leads; select capacitors with robust mechanical construction.

Industrial Ecosystem

Compatible With

Interchangeable Parts

Compliance & Inspection

Tolerance
Capacitance tolerance typically ±1% to ±5%; voltage tolerance as per rated DC voltage with derating for reliability.
Test Method
Capacitance measured via LCR meter at specified frequency (e.g., 1kHz); leakage current tested with applied DC voltage; dielectric absorption assessed via charge-hold-discharge-recovery cycle per industry methods.

Buyer Feedback

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"The technical documentation for this Hold Capacitor is very thorough, especially regarding technical reliability."

"Reliable performance in harsh Computer, Electronic and Optical Product Manufacturing environments. No issues with the Hold Capacitor so far."

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Frequently Asked Questions

Why is dielectric absorption important for a hold capacitor?

Dielectric absorption causes a capacitor to slowly release or 'remember' a previous charge state, leading to voltage errors during the hold phase. Low dielectric absorption materials (e.g., polypropylene) are essential for high-accuracy S/H circuits to minimize this memory effect and ensure signal fidelity.

How does capacitor value affect S/H circuit performance?

A larger capacitance reduces droop rate (voltage decay during hold) but increases acquisition time (time to charge during sample) and requires more drive current. A smaller capacitance allows faster sampling but is more susceptible to droop and noise. The value is optimized based on required sampling speed, hold duration, and accuracy.

Can I contact factories directly?

Yes, each factory profile provides direct contact information.

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