Scribd
Upload
2K views2 pages

TL431 Ic Testing

The document describes a circuit that can be used to dynamically test TL431 voltage regulators. The circuit uses a 12V input voltage and resistors to obtain a fixed 5V output voltage when the regulator is functioning properly. Pressing the switch should drop the output voltage to half the initial reading, or 2.5V. A reading of 0V at the output indicates the regulator is defective and needs replacing. The circuit provides a way to evaluate TL431 regulators that is more reliable than simply using a multimeter.

Uploaded by

sachin
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
2K views2 pages

TL431 Ic Testing

The document describes a circuit that can be used to dynamically test TL431 voltage regulators. The circuit uses a 12V input voltage and resistors to obtain a fixed 5V output voltage when the regulator is functioning properly. Pressing the switch should drop the output voltage to half the initial reading, or 2.5V. A reading of 0V at the output indicates the regulator is defective and needs replacing. The circuit provides a way to evaluate TL431 regulators that is more reliable than simply using a multimeter.

Uploaded by

sachin
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
You are on page 1/ 2

Collection by Pravin Mevada

Tests on the TL431 regulator only with the use of the multimeter cannot determine whether the
component is in good condition or not.
As this component is widely used in switching sources of most current appliances, testing this
component is a good practice.

Although its symbol in the schematic resembles a zener diode, this component is a high stability
thermal voltage regulator circuit.
For this reason, the Meter is not recommended to evaluate the status of this IC.

Pravin Mevada

In the image below we have a small circuit that can test this component dynamically.
dynamically

Pravin Mevada
With a voltage of 12V at the input of the circuit (VIN) and with the values of the resistors shown in
the circuit, we can obtain a fixed voltage of 5V at the output (VOUT).
A multimeter must be used to check this voltage.

If the voltage found at the output


tput is close to 5V, the component is OK.

To confirm that the component is in good condition, press the SW1 switch.
The 5V voltage should drop to 2.5V (half the first reading voltage).

A 0v voltage at the output indicates that the component is defectiv


defective
e and must be replaced.

Grades:
- The initials before "431" may vary depending on the manufacturer.
- The capacitor is optional.
- Other output values can be calculated using the formula below.
- The output voltage may vary depending on the tolerance o off the resistors used and the 431 itself.
The ideal is to test with a new TL431 to have a voltage reference on the output.
From there, you can test other components.

Pravin Mevada

You might also like