Digital multimeter safety tips include inspecting test leads for damage and ensuring any capacitors are discharged before taking resistance measurements. When measuring resistance, the meter generates a small current to determine the component's resistance. External voltages can damage the meter or provide inaccurate readings. It is important to disconnect power sources and discharge capacitors before taking resistance measurements to avoid electric shocks or damaging the meter. Digital multimeters should also only be used in resistance mode when checking components to prevent damage.

1. Digital Multimeter Safety Tips.

3. Digital Multimeter Safety Tips.

4. Inspect Leads,
Before using test leads, perform an inspection to ensure the leads are safe to use and able to conduct electrical signals accurately. In most common
circumstances, the physical condition of the test leads is the most important factor affecting your measurements.

5. Digital Multimeter Safety Tips.

6. Digital Multimeter Safety Tips.

7. Analog Multimeter Circuit Diagram.

8. Volt Meter Work Series Circuit Current Meter Work Parallel Circuit

9. Ohm Meter Circuit Diagram.
When the meter is in “resistance” mode, it uses a small internal battery to generate a tiny current through the component
to be measured. By sensing how difficult it is to move this current through the component, the resistance of that
component can be determined and displayed. If there is any additional source of voltage in the meter-lead-component-
lead-meter loop to either aid or oppose the resistance-measuring current produced by the meter, faulty readings will
result. In a worse-case situation, the meter may even be damaged by the external voltage.
To avoid electric shock, disconnect power to the unit under test and discharge all capacitors before taking any resistance measurements.
and unplug the line cords.
An energized circuit will damage the meter and can be harmful to you.

10. However, measuring the resistance from one ground connection to
another on a powered circuit is unlikely to cause any damage,
though it's not best practice.

11. Pressure Switch , Multi Meter Safety ,
220 / 110 & 24 Volt . Sample Circuit

12. WARNING:
Ensure capacitors in a circuit under test are discharged. Again when measuring resistance values in a circuit, it is necessary
to ensure that any capacitors in the circuit are discharged. Any current that flows as a result of them will cause the meter
May Be Damage & reading to be altered.

13. Digital Multimeter Circuit Diagram.
Digital multimeter is costly, so avoid uses that are likely to damage it.

14. .
Field devices.
Causes of PLC control system failure,
About 80 percent of PLC failures are a result of field devices,
Input/output (I/O) module failure
or power supply issues.

15. Causes Of Damage,
Bailey Controls IMDSI02 / IMDSO04
infi 90 Digital Input / Output Slave Module.

16. Fly back diode for relay spike protection.
A fly back diode is used to protect circuits against the reverse voltage generated by removing
power from a relay & Solenoid Coil.
( Digital Output Slave Module ) Field , Relay / Salonied Coil

17. Checked Thermocouple In Field,
One very important thing to remember about measuring
resistance is that it must only Check Thermo Couple When the
meter is in “resistance” mode, it uses a small internal battery to
generate a tiny current through the component to be measured.
The batteries inside the case provide the source of power for
the ohmmeter. result in damage to the PLC Circuit
and possible harm to you.

18. Checked Thermocouple In Field,
Measure Temperature,
Field CCR

19. Causes Of Damage,
One very important thing to remember about, Power Supply Voltage Switch.
The power supply voltage switch, sometimes called the voltage selector switch, is a small switch located on the back of most desktop computer
Power supply Unit (PSUs).
This small switch is used to set the input voltage to the power supply to either 110v/115v or 220v/230v