# What is the definition of d.c component in standard IEC 60601-2-10?

#### Onion_Mr

##### Registered
Hi guys,
I’m confused about the definition of d.c component in IEC 60601-2-10. I cannot find any definition in IEC terminology. Is the d.c component same as d.c offset? Does someone meet d.c component with TENS or EMS product? Can someone illustrate the d.c component.
How can I measure the d.c component in oscilloscope[FONT=&#23435]？[/FONT]Can I count the number of vertical divisions between the zero line using AC coupling?
Does the output wave (ie. Rectangular wave, irregular wave and sawtooth wave) effect the d.c component?
I appreciate someone can help this.

N

#### nikolaos

Hi Onion_Mr,

I don?t think the "DC components" definition in IEC 60601-1-10 is different from the definition in any Electronics textbook.
The DC component is the constant voltage added to a AC waveform. For example, the true average voltage of sine wave is zero. When a AC symmetric waveform has a DC component, the average voltage is equal to the DC voltage, because opposite waves cancel each other leaving only the DC component. You can measure the DC component with an oscilloscope if the average voltage measurements is available. The value can be positive of negative if the waveform is shifted up or down with respect the reference ground.

Hope this help

W

#### wally4u

I would classify a D.C. component as any asymmetrical waveform generated.
Basically a square wave with no negative DC offset (i.e. 0 - 1V) would be a d.c. waveform.
examples would be:
TENS asymmetrical
Trabert

#### Onion_Mr

##### Registered
Hi Onion_Mr,

I don?t think the "DC components" definition in IEC 60601-1-10 is different from the definition in any Electronics textbook.
The DC component is the constant voltage added to a AC waveform. For example, the true average voltage of sine wave is zero. When a AC symmetric waveform has a DC component, the average voltage is equal to the DC voltage, because opposite waves cancel each other leaving only the DC component. You can measure the DC component with an oscilloscope if the average voltage measurements is available. The value can be positive of negative if the waveform is shifted up or down with respect the reference ground.

Hope this help

Nikolaos,