Ideal diode circuit dc offset question

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Jump to Latest
T

ttako

Member
Joined 2003
Hi,

I would like to build a level meter, where i also need a kindo of "signal" led, with a threshold level of ca 80mV....

My problem is right now, that i have much more dc offset at its output. (~200mV)

Is there a good way to decrease this DC offset significantly?

I use 1N4148 and an OP07 as opamp
It all runs from +/-12V dc
 

Attachments

  • image.png
    image.png
    182.2 KB · Views: 83
Elvee

Elvee

Member
Joined 2006
ttako said:
My problem is right now, that i have much more dc offset at its output. (~200mV)

Is there a good way to decrease this DC offset significantly?
Click to expand...
The typical bias current for the 339 is 25nA. 25.10e-9 x 10.10e6=250.10e-3, that's 250mV.
The solution is to reduce the 10meg resistor (and scale the capacitor accordingly), or to opt for a comparator having a negligible input current: the TLC374 or CMP04 are pin-compatible examples
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Top Bottom