I am quantifying the characteristics and performance of a device that includes a photodiode.
Currently my set up involves the photocurrent generated by a photodiode going into a pre-amplifier and then additional signal processing elements.
My new experiment involves the use of low current ammeter. The meter is different from a normal ammeter in that it sinks the current rather than being a low impendence element in series in the circuit. I need to be able to switch between the photocurrent flowing into pre amplifier and flowing into the ammeter.
Obviously I could add a switch to the PCB, however(for reasons I wont go into) I cant access the board during the test. There is however cable coming off the PCB.
I am thinking of using a miniature PCB single pole double throw relay, which I could activate remotely. I've read a few of data sheets and some make reference to a minimum contract current. Values around 10mA seem the norm. As I will be measuring currents in the 1-100nA range I don't know if a relay is a suitable component.
Can anyone suggest a suitable approach and components to use?
Graeme
Currently my set up involves the photocurrent generated by a photodiode going into a pre-amplifier and then additional signal processing elements.
My new experiment involves the use of low current ammeter. The meter is different from a normal ammeter in that it sinks the current rather than being a low impendence element in series in the circuit. I need to be able to switch between the photocurrent flowing into pre amplifier and flowing into the ammeter.
Obviously I could add a switch to the PCB, however(for reasons I wont go into) I cant access the board during the test. There is however cable coming off the PCB.
I am thinking of using a miniature PCB single pole double throw relay, which I could activate remotely. I've read a few of data sheets and some make reference to a minimum contract current. Values around 10mA seem the norm. As I will be measuring currents in the 1-100nA range I don't know if a relay is a suitable component.
Can anyone suggest a suitable approach and components to use?
Graeme
