Baratron Controller

The last part of the manifold is the pressure gauge. The baratron Farny used needs a supply of +15V and -15V, and gives a linear output of 0-10V for 0-100 torr. I will use a baratron that gives measurements in psi if available to keep everything in SI units.

Farny built a simple power supply using two 15V zener diodes and two 15Ohm resistors. The input power is 40V and the circuit outputs +-15V. Farny used a cheap voltmeter to display the output

It’s range is 0-10V so when the baratron output is 5.25V it means 52.5 torr, so the reading has to be multiplied by 10 to get the right readout in torr. When I construct my setup I will use a more elegant solution.

The baratron is not dependent on the type of gas inside like pirani or thermocouple gauges are, and shows the right pressure for all gases.