Loading and Buffers

Buffer Isolates the Filter Load

An ideal buffer keeps the source-facing side unloaded. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Without isolation the source drops voltage

The direct load case drops 4 volts across the source impedance.

Vdrop=4 VV_{\text{drop}}=4\ V
Loaded sourceThe source drop is checked by the divider.2 ohm6 ohmV12 V+-4 V+-12 Vresistive

The ideal buffer presents an open input

The buffer case has source current 0 amperes and source drop 0 volts.

Isource=0 A,Vdrop=0 VI_{\text{source}}=0\ A,\quad V_{\text{drop}}=0\ V
Ideal buffer inputThe open input rejects a finite bridge path.V16 VV16 V+-0 V+-16 Vbuffer