Test with a multimeter

Op-amp (LM358)

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Now: VCC to GND: short circuit check

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Pin 1: OUT A (OUT) Pin 2: IN− A (IN−) Pin 3: IN+ A (IN+) Pin 4: GND (GND) Pin 5: IN+ B (IN+) Pin 6: IN− B (IN−) Pin 7: OUT B (OUT) Pin 8: VCC (VCC)

Red probe Not connectedBlack probe Not connected

Hold the probe and drag it to the tip of a leg. Tapping works too: first pick the probe, then the leg.

Set the range to Ω (resistance).

Test setup: Setup: it powers with 5 V; input A is 2 V, input B is 1 V and both outputs are tied to their own inverting input (voltage follower). Press the “Power on” button.

Measure step by step

Between the supply pins of the op-amp (VCC-GND) there must be no short circuit when it is unpowered. In the setup, two op-amps are connected as voltage followers: the output follows the input. Input A is set to 2 V and input B to 1 V. The multimeter cannot measure the IC’s temperature, behaviour under load or speed: this test only shows that there is no short circuit and that the setup gives the expected voltages. A good result means “it could not be proven faulty”.

Isolate the IC from the circuit and measure it unpowered. Do not use the Ω range on a pin that has voltage on it.

  1. 1VCC to GND: short circuit check
  2. 2Power on: VCC voltage
  3. 3Power on: input A (IN+)
  4. 4Power on: does output A follow the input
  5. 5Power on: does output B follow the input
  6. 6Power on: supply current