Recent content by darkwhite87

"low noise" as in i need to amplify something in the order of "pA" in the background level of "nA"... i would be amplifying a pulse with width in the nanoseconds range, i would guess most of the frequency component are in the high range, so I may be able to withstand a amplifier which is bad at...

Does anyone know how to build a low noise current amplifer that has wide bandwidth from ~10Hz to ~1Ghz, and together with high sensitivity (can amplify ~nA/pA) I need one for my project to amplify photocurrent, but am struggling to find any suitable products or design guides... cheers

semiconductor lasers can be much more efficient because of direct band gap materials. From memory the efficiency of semoconductor lasers is at least 100x better than gas lasers...but the downside of it is it can not handle too high power..or the PN junction will breakdown..

Thanks Proton, but I looked through mcmaster, the timing relays are in the range of second~hours while I need a delay in the order of milliseconds. Secondly I think I don't need a timing "relay". I want to control my relay with a time delay device.

Hi guys, Background: There are 2 relays, A and B that needs to be controlled (24V) And a signal generating device that composes of a push button and an adjustable mechanism for timing delay between the 2 signals. (this is what I want to design) Specification: I want to design a...

In the case of an open-circuit test of transformer, when I increase the supply voltage, i realize the magnetising reactance (Xm) decreases, why does this happen?

A photodiode generates current due to the light intensity that it senses, maybe u can try it.

Thanks for the suggestions

Suppose I have 2 input signals V1 and V2, And I want my output signal to alternate from V1 to V2 and so on at a particular frequency. Any idea what components can help me to achieve this goal?? Thank you

When using small signal analysis, the bypass capacitor shorts out midband, so emitter is grounded, also said by corneo in #6

For the first simplification I used the Thevinin's Theorem. Looking at the circuit to left of base, the total resistance is paralleled RB1 and RB2 (To find thevinin's resistance ground the voltage supply i think), and then find the thevinin voltage. so..is it really wrong?

I have read some texts myself but the explanations i read still leave me some queries. Below I have copied some text from wiki. From the text is in bold and my queries are in italic. Can someone please help me with my understanding, THANKS! Class A amplifiers are the usual means of...

Thanks everyone. I have now tried to do this question again with your suggestions, please check my solution as attched.

Thanks for the hint, this is wat i have done so far as implementing pi-model. The input resistance should be 33k//68k//R_pi (pi-model circuit attached) But how do i obtain the value for R_pi, is it possible to obtain it from the given data "current gain of transistor is 400"?? if not, why...

Please view the attached circuit. I will be appreciated for any suggested answer, thanks! Q1) Calculate the dc input resistance of the transistor amplifier shown in figure 1 below if the current gain of the transistor is 400: I need some help on this one, i don't know the relationship...