Spark Logic

1N914 switching diode connection guide

1N914 switching diode DO-35 (DO-204AH) wiring guide with power, signal assignments, and bench checks.

DO-35 (DO-204AH)

2 contacts Current package

Vishay · Axial glass body · 3.9 mm maximum body length · black cathode band.

Tape-and-reel ordering code, same glass diode and band.

Set up a current-limited fixture

Required

Turn off a regulated 5 V bench supply and put a 1 kΩ, 0.25 W resistor in series with its positive output. Use a 10 mA supply limit for this test. Identify the black cathode band before fitting the diode.

  • Bench supply
    • Current-limited +5 V supply
    • R1.1
  • Supply return
    • Bench supply return
    • Meter common

Bench checks

  • With power off and the diode removed, verify about 1 kΩ through the series resistor. It limits a short at the test node to about 5 mA even before the supply’s current limit acts.

Vishay 85622 Rev. 2.2, pp. 1–2. The fixture voltage, resistor and limit are bench choices.

Connection scenarios

Check forward conduction

With the supply off, place the unbanded anode on the resistor side and the banded cathode at ground. Reapply 5 V after checking the series resistor.

5 volt supply through R1 to the 1N914 anode, with cathode at the supply return.+5 VR1 1 kΩD1 1N914Test node0 V
  • Bench supply
    • Current-limited +5 V supply
    • R1.1
  • Diode test node
    • R1.2
    • A (1)
    • Voltmeter positive probe
  • Supply return
    • Bench supply return
    • K (2)
    • Voltmeter common

Bench checks

  • With the meter common on the cathode, the test node should read roughly 0.6–0.8 V at room temperature. A 0.7 V reading gives about 4.3 mA through R1. A test-node reading close to +5 V suggests a reversed or open part.

Vishay 85622 Rev. 2.2, p. 2 and Fig. 1. The 5 V fixture and 1 kΩ resistor are bench choices.

DO-35 (DO-204AH) wiring map

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

DO-35 (DO-204AH)
Side view with the cathode band on the right. Map numbers identify the two leads in this drawing.
Selected pin details

2 · K

Cathode · Outputs

Lead nearest the black band. The bar on the schematic symbol marks this terminal.

Vishay 85622 Rev. 2.2, pp. 1–2

Electrical limits · Pin in the reference

Models and documents

Vishay 1N914TR and 1N914TAP share the same DO-35 package and electrical limits. Check the applicable manufacturer sheet for other brands or suffixed 1N914A/B devices.

1N914TR
Tape-and-reel ordering code, same glass diode and band.
1N914TAP
Ammopack ordering code, same glass diode and band.