Overview
ISO 10330:2002 - "Photography - Synchronizers, ignition circuits and connectors for cameras and photoflash units - Electrical characteristics and test methods" - defines electrical requirements and standardized test methods to ensure reliable firing of photoflash units when coupled to cameras. The standard covers the camera synchronizer, the ignition circuit in the photoflash, the interconnecting cable, and the procedures to verify positive and repeatable flash firing.
Key topics and requirements
The standard specifies measurable electrical characteristics and test setups. Important technical requirements include:
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Maximum voltages and currents
- Voltage across synchronizer and ignition circuit terminals: ≤ 24 V DC
- Synchronization current through camera synchronizer: ≤ 100 mA
- Current through ignition circuit terminals in any one photoflash unit: ≤ 30 mA
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Ignition circuit firing test
- A 4.4 MΩ resistance across ignition terminals and a defined pulse waveform (pulse amplitude V = 1.6 V) must reliably fire the photoflash unit.
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Dynamic synchronizer behavior
- Defined starting voltage = 21 V, on‑state upper limit = 1.5 V.
- Tests use a 24 V DC supply and 240 Ω series resistor to verify timing: for mechanical switches at least one interval within 150 µs must be ≥ 10 µs at ≤ 1.5 V.
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Leakage and cable characteristics
- Synchronizer leakage current at 24 V: ≤ 5 µA
- Cable resistance (shorted at one end): ≤ 2 Ω
- Cable capacitance: ≤ 3 000 pF
- Cable insulation resistance: ≥ 50 MΩ at 100 V DC
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Test methods
- Detailed test circuits and oscilloscope/pulse-generator setups are specified to measure ignition operation, dynamic characteristics, and leakage current.
Applications and users
ISO 10330 is practical for stakeholders involved in photographic equipment design, testing and certification:
- Camera and photoflash manufacturers (design validation, interoperability)
- Accessory and connector makers (shoe, plug and socket compatibility)
- Test laboratories and quality assurance teams (electrical verification, compliance testing)
- Product safety and standards engineers ensuring reliable flash synchronization
Implementing ISO 10330 helps minimize misfires, electrical interference between parallel flash units, and compatibility issues across camera/flash combinations.
Related standards
Normative references cited in ISO 10330 include:
Keywords: ISO 10330, synchronizers, ignition circuits, photoflash, camera synchronizer, flash connectors, electrical characteristics, test methods, leakage current, cable capacitance.
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