SMD marking
20H
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.
20H on a chip resistor
1.58 kΩ
1.58 kΩ resistor, 1%
EIA-96 precision code: 20 selects 1.58 from the E96 series and H multiplies by 1000. These are 1% parts.
Check it with a meter
Lift one end and measure across it. A good one reads 1.58 kΩ within 1%. Measuring it in circuit reads the parallel combination of everything around it, which is almost always lower, never higher: well above 1.58 kΩ on the board is a fault. Open, or well above 1.58 kΩ, means it has failed: burnt, cracked or corroded. That does not change what to fit: the marking still says 1.58 kΩ. A burnt resistor usually means the part it feeds drew too much, so find that before fitting a new one.
On a transistor or diode body, 20H is a part code instead. Those parts are listed below.
The only part printed 20H in our tables
ESDUNE20VB1
- What it is
- ESD protection diode
- Maker
- JSCJ
- Package
- Not recorded
- Pins
- Not recorded
- Details
- ESD protection diode, VRWM 20 V
- Source
- From the manufacturer's datasheet
Is it dead?
Diode range, from the protected line to ground, part lifted if you can.
Working, it reads
A one-way part reads about 0.6 to 0.8 V forward and open in reverse. A two-way part reads open both ways. Arrays with several lines read as the datasheet's diagram draws them.
Dead, it reads
- From the line to ground, the same reading both ways, near 0 V with a continuous beep: shorted.
- A reading both ways on a one-way part: leaky.
- A one-way part open both ways: failed open.
- On the board:
- On the board, a line reading shorted to ground can be this part or anything else on that line. Lift it: if the short goes with it, it has failed.
- Compare:
- The same part on the next line or connector pin is the healthy reading to compare with.
- Watch for:
- A two-way part reads open both ways when it is good, exactly like one that has failed open. The meter cannot tell them apart; an identical part on the next line can.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
Open this in the search to correct a character or try another package.