Voltage Reducer Circuit (other than resistor divider)

[ADWSystems]

I apologize in advance for the lack of a circuit diagram. I do not have access to a schematic cad package for the moment.

The basis of the circuit is a temperature controller. LM34 temperature sensor input (10mV/1degF), MC14072 for x10 gain, LM393 comparator. I found a 0-200mV LED display to show the temperature if the LM34 output is divided by 10.

I would also like to be able to display the LM393 threshold. If I use the opamp output (100mV/1degF) divided by 100 and the threshold divided by 100 (selected by a switch) I can display either. in short, displaying the voltages at the comparator - or + inputs. But using a 9:1 (900k:100k) resistor divider from either point affects the voltage at that point. I was thinking of using the other half of the MC14072 as a voltage follower with a 10k pull-up and a 900k/100k resistor divider to ground. Will this work?

 

[Nigel Goodwin]

A buffer should be fine, but so would suitable selection of the various resistors in the potential dividers.

However, if you've already got a spare opamp that's an easy solution.