Go Down

Topic: Measuring microamps (Read 2 times) previous topic - next topic

stoopkid

I know it's not too likely, but I was wondering if there was a way to fairly accurately measure between about 100-1250 microamps without any specialized hardware. I'm interested in automatically measuring the gain of germanium transistors in two different situations automatically as shown at the bottom of this page (#26).

Thanks

bubulindo

Last I tried something like this it was to measure a few TOhm.

I used one or two op-amps from TI... I believe it was OPA128 or something like that. The price for each of those was around 20 euro for small quantities and the care that was needed in the board design was a real nightmare. The project worked somewhat, but the scale involved (down to a few kOhm) and the non-linearity made it too problematic to consider bringing it to market.
Eu não sou o teu criado. Se respondo no fórum é para ajudar todos mediante a minha disponibilidade e disposição. Responder por mensagem pessoal iria contra o propósito do fórum e por isso evito-o.
Se realmente pretendes que eu te ajude por mensagem pessoal, então podemos chegar a um acordo e contrato onde me pagas pela ajuda que eu fornecer e poderás então definir os termos de confidencialidade do meu serviço. De forma contrária toda e qualquer ajuda que eu der tem de ser visível a todos os participantes do fórum (será boa ideia, veres o significado da palavra fórum).
Nota também que eu não me responsabilizo por parvoíces escritas neste espaço pelo que se vais seguir algo dito por mim, entende que o farás por tua conta e risco.

Dito isto, mensagens pessoais só se forem pessoais, ou seja, se já interagimos de alguma forma no passado ou se me pretendes convidar para uma churrascada com cerveja (paga por ti, obviamente).

terryking228

Hi,

Take a look at http://www.keithley.com/knowledgecenter  and get a couple of their handbooks.

In Semiconductor test, we used their "Electrometer" and other instruments. Measuring Picoamps requires shielding/guarding and excellent insulators.
Regards, Terry King terry@yourduino.com  - Check great prices, devices and Arduino-related boards at http://YourDuino.com
HOW-TO: http://ArduinoInfo.Info

Magician

Simple resistor will do great job as current/voltage transformer, analogRead would digitize results for you.
For 100 microAmpers * 1 kOhm = 0.1V ( to stay away from noise floor),
and 1250 * 1 kOhm = 1.25 V accordingly.

GoForSmoke

Would a linear analog Hall sensor be able to pick up on the moving charge field?

I find it harder to express logic in English than in Code.
Sometimes an example says more than many times as many words.

Go Up