Hello,
I am looking to replace an Analog Devices (Part# REF10 ) 10 volt voltage reference device in an existing circuit. The chip supplies 10 volts to a number of n/o and n/c switch contacts that have a shunt and end-of-line resistors fitted to them. The ADC of a PIC 16F628 then measures the circuit condition through a couple of divider resistors. The REF10 would be ideal but for the fact that the switch resistors are low values and as such draw more current than the it can comfortably supply. I have thought about using a simple arrangement of a 7809 1 amp voltage regulator to supply the 10 volts and using a resistor in series with its ground lead to 'tweak' the output up to 10 volts above ground. My only worry is that the output voltage might be a bit noisy which could upset the PIC's ADC converter.
Does anyone think this could be a problem ?
TIA,
Colin