Skip to content
WhatSMDSign in

SMD code N78

Marking codes are not standardised, and the same code is reused by unrelated makers for unrelated parts. Below is every part in our tables printed with it, and any printed with a code that is easy to misread as it, from the manufacturers' own marking tables and published code lists.

N78 on a chip capacitor

780 pF

780 pF capacitor

The n is both the decimal point and the unit: 780 pF.

Check it with a meter

Lift one end and measure it on a capacitance range. A good one reads close to 780 pF. In circuit the meter also sees everything connected across it, so the reading means little until it is out. A failed one usually reads near 0 Ω, or a steady low resistance, on the ohms range, often from a crack. On the board a shorted capacitor shorts its whole rail. A failed reading does not change what to fit: the marking still says 780 pF.

On a transistor or diode body (SOT-23-5, SOT-89-5, USP-6C), N78 is a part code instead. Those parts are listed below.

2 parts are printed N78

Not sure which one you have?

Answer up to 4 quick questions and these 2 parts are ranked, with a meter test that settles it. It works on a dead part too.

Digital transistor (NPN, resistors built in), 3 pins, all Diodes Incorporated. What differs:

  • DDTD142TCSOT-23SOT-23
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    Diodes Incorporated
    Package
    SOT-23
    Pins
    3
    Details
    Si-npn-Digi: Sw, 50V, 500mA, 200mW, 200MHz, R1=0,47k
    Source
    Published code list

    Is it dead? The meter test is below: Digital transistor.

  • DDTD142TUSOT-323SOT-323
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    Diodes Incorporated
    Package
    SOT-323
    Pins
    3
    Details
    Si-npn-Digi: Sw, 50V, 500mA, 200mW, 200MHz, R1=0,22k
    Source
    Published code list

    Is it dead? The meter test is below: Digital transistor.

Is it dead? One meter test per kind

Parts of the same kind are tested the same way, so each test is here once. Each part above points to its own.

Digital transistor

Ohms range, part lifted. The datasheet gives the built-in resistors: R1 in series with the base, R2 from base to emitter.

Working, it reads

Base to emitter reads about R1 plus R2 either way round, about 20 kΩ on a 10 k and 10 k part, give or take their wide tolerance. Collector to emitter reads open. A part with no R2 reads a junction behind R1 one way instead.

Dead, it reads

  • Collector to emitter the same both ways, near 0 Ω with a continuous beep: shorted.
  • From the base, open or far above R1 plus R2: R1 has failed. Static damage shows here most often.
  • Base to emitter near 0 Ω: failed short.
On the board
this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
Compare:
The readings depend on the resistor values, so an identical part elsewhere on the board is the surest reference. Measure it the same way.
Watch for:
On the diode range a good part with 10 kΩ resistors reads open on every pair, so a good part looks dead there. Use the ohms range.

A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

Printed with a code easy to misread as N78

One character differs, and it is one that is easy to confuse under a lamp. Each code has a page of its own.

Did you find your part?

Open this in the search to correct a character or try another package.