EP 70 - Récupération de composants électroniques . . Bon plan ?

Overview

The video explores whether it’s worthwhile to salvage (recover) electronic components from old circuits—especially industrial equipment—and whether those parts can be reused in new projects. The speaker lays out an approach with pros/cons, then gives practical selection criteria by circuit type and the testing requirements needed to verify parts before reuse.

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What the creator recovers (systematically) — main criteria

Electromechanical parts

• Contactors and switches
  • Includes high-current units (e.g., ~30/40A contactors salvaged from solar inverters).
• Relays
  • Preferred because they can be functionally reused if tested.
  • The speaker likes using relays with:
    • Different coil supply voltages
    • Different contact configurations
  • But they insist on checking contact quality before reuse.

Protective surge components

• Varistors (MOVs)
  • Collected even though they must be tested.
  • Testing expectations:
    • When unpowered: very high resistance (effectively open)
    • Near operating conditions: they should behave like a short/conduct
• Often mentioned alongside fuses as part of surge protection setups.

Mechanical / wiring / interconnection parts

• Screw terminals, terminal blocks, and small screw terminals
• Connectors (selectively)
  • Sometimes considered not worth it if only the missing mating half makes the salvage less useful.
• Mounting hardware
  • Screws, fixings, insulation covers/sheets, and metal/aluminum blocks that can be reworked

Some power magnetics and power passives

• Transformers
  • Example: 220V primary with multiple secondary rails (e.g., ~7.5V each).
• Coils / inductors
  • If the coil itself isn’t usable directly, the speaker may recover the former/winding or rewind for reuse.
• Power resistors
  • Reused (specific power ranges are mentioned).
• Large capacitors
  • Sometimes recovered, but the speaker warns that electrolytic/electrochemical capacitors age fastest.

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What the creator does NOT recover (or rarely)

Semiconductors and active devices

• Does not recover:
  • MOSFETs, IGBTs, thyristors, transistors, and other active devices
• Reason given:
  • If SMD/through rework is needed, parts are stressed multiple times (original stress + removal + re-soldering), causing premature “aging.”

SMD components

• Explicitly not recovered due to the additional stress cycles from handling/removal.

Parts that are too damaged or not worthwhile

• Example: a relay that is faulty/fallen during transport is discarded.
• Some circuits are discarded when they contain mostly SMD components with little salvage value.

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Component-by-component testing / “how to judge”

Relays

• Must test/inspect that the contacts work correctly before reuse.

Varistors (MOVs)

Must measure/test their behavior, expecting:

• Very high / near-infinite resistance when unpowered
• Conducting / effectively short behavior near operating condition

Electrolytic capacitors (major technical point)

• If salvaging electrolytics, the speaker emphasizes measuring ESR (equivalent series resistance).
• Reference method mentioned:
  • A table (in the video description) listing ESR expectations vs capacitance and nominal voltage
• Rule of thumb:
  • Lower ESR = healthier capacitor
• Example estimate:
  • For 1000 µF / 35V, ESR may be around ~0.x Ω (approximate).
  • If ESR is several ohms, the capacitor likely needs replacement soon.

ESR measurement tools

• Mentions a lab tool (Dr.EE) that costs about €200
  • Can measure capacitance and SR/ESR
• References earlier background material:
  • e.g., EP06 “capacitors part 3” for ESR definition

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Practical “circuit triage” examples (what’s valuable per circuit)

Relay-based control boards

• Described as the most interesting
• Targeted relays typically include:
  • ~24V coils
  • Up to ~6A switching

Boards dominated by SMD parts

• Mostly discarded
• Sometimes only one scarce through-hole part might be saved (e.g., a through-hole micro switch).

Mixed SMD + through-hole boards

Recovered items include:

• Micro-switch buttons
• The display (potential Arduino use)
• 12V relays
• Varistors
• Selected passive/power items such as:
  • Transformers
  • Fuse holders

A 60V DC coil contactor was judged not useful due to voltage mismatch with likely needs.

Solar inverter control electronics

Targeted salvage includes:

• Faston / PCB wire terminals for thick wiring
• Certain terminal blocks
• Varistors
• Power resistors
• Potentially expensive high-voltage capacitors, but ESR testing is again emphasized.

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Key takeaways / “position”

• Salvage is most worthwhile for:
  • Electromechanical parts (relays/contactors)
  • Connectors/terminal blocks
  • Selected passive power components that can be verified

• Avoid:

  • SMD components
  • Active semiconductors because of extra handling/solder stress and likely degraded reliability.

• The core deep reuse requirement highlighted is:

  • ESR testing for electrolytic capacitors, using reference tables and proper measurement tools.

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Main speakers / sources

• Single video presenter (the creator demonstrating their component recovery examples)