![UV DIODE AMP](UV_Diode_amplifier_two_stage.png)

This is my working photo-diode amplifier that responded well the butane gas flames in the lab.
This worked well with manf:GUVB-S11DCT-ND ( $240 \rightarrow 320nm$  UVB) and manf:GUVV-S10SD ($240nm \rightarrow 320nm$ UVA). Note the 7M5 feeding the vref to the first op-amp is necessary for current balancing. A multi-meter will disturb this first stage as it is amplifying pico-amps (probably!)