Spark Logic

CR123 photo lithium cell connection guide

CR123 photo lithium cell Cylindrical cell wiring guide with power, signal assignments, and bench checks.

Cylindrical cell

2 contacts Current package

Energizer · Ø 17 × 34.5 mm

Check holder polarity

Required

Fit the cell into the matching insulated holder with the positive contact on the plus side. Disconnect all loads and any external supply. Use a voltmeter in DC voltage mode.

  • Positive lead
    • + (1)
    • Holder positive
    • Meter red probe
  • Return

Bench checks

  • A positive reading near 3 V confirms the polarity of the open-circuit measurement.
  • If the sign is negative, remove the cell and trace the holder terminals again. A plausible open-circuit voltage alone does not establish remaining capacity.

Energizer EL123AP datasheet, form 123GL0918, p. 1

Connection scenarios

Check voltage under a small load

Remove the cell, connect a 1 kΩ resistor across the holder leads and insert the cell again. Measure voltage across the resistor with the voltmeter in DC voltage mode.

  • Holder positive
  • Holder return
1 kΩ between Holder positive and Holder returnHolder positive1 kΩHolder return

Bench checks

  • At 3 V, the resistor draws about 3 mA. Use the measured voltage divided by resistance to calculate the test current.
  • If the loaded voltage drops sharply, remove the cell and check the contact resistance and cell condition before reconnecting the device.

Energizer EL123AP datasheet, form 123GL0918, p. 1. The resistor and current are bench test choices.

Cylindrical cell wiring map

Highlighted contacts are used in the required step or selected circuit. Select a contact to inspect it.

Cylindrical cell
Side view with positive on the left and negative on the right. The numbers identify the two terminals in this map.
Selected pin details

1 · +

Positive terminal · Power

Raised positive contact at the cap end.

Energizer EL123AP datasheet, form 123GL0918, p. 1

Electrical limits · Pin in the reference

Models and documents

This map covers the bare cell. Match the holder to the exact size and terminal orientation. For factory tabbed or wired versions, use the drawing for the full ordering code.

EL123AP
Energizer · bare cell · Ø 17 × 34.5 mm