The differential and common mode input impedance of the op amp transistor models ...
[Eop]
Tuesday, September 28, 2021
The circuits for determining the AvOL (open loop gain) of the op amp
´ 741 ::
LM324 equivalent transistor model ::
[Eop]
Sunday, September 26, 2021
Univeral Op Amp for probing the CM input range
(in pictures)
A universal ("enough") Op Amp
Old CM Inp-rg. test
New CM Inp-rg. test
[Eop]
Saturday, August 7, 2021
Pos. fbk. Op. Amp. - (spice) noise
see also : Dif. Pos.-fbk. op.-Amp.
about LM324 , uA741 , TL071 , LM308 :
compared to conventional biasing schemes :
the pos.-fbk scheme has more poor noise and frequency characteristics but it enables to use the feedback shoulder to excite a crystal or reduce the input current . . .
[Eop]
Monday, July 19, 2021
another inductance meter concept
a dummy sine generator :
Op Amp version :
the x = Δf( L( f ) ) = – 2 · Δf / ( (2π) ² · C · f ³ )
where Δf = f(40uH) - f(42uH)
the y = ΔL( f ) = L(42µH) – L(40µH)
and the best match for the ΔL is a non-std. average E( x , y ) = 2 · x · y / ( x + y )
[Eop]