Linked Questions

5 votes
8 answers

Lighting either of two LEDs, or none, based on digital input

I ran into a problem which I tought was extremely simple, and after giving it some thought for more than 2 hours I had to recognise it actually is quite complicated. The problem is the following: I ...
Bregalad's user avatar
  • 378
0 votes
3 answers

Measurement of the beta of a BJT with a multimeter

When we measure the beta of a BJT transistor with a multimeter, which beta is giving us, the maximum, the average or the minimum beta and under what conditions of Ic and Vce? Thanks
Mario's user avatar
  • 227
3 votes
3 answers

Op-amp voltage boost circuit : how does it work?

I want to boost the output voltage of op amp to a higher value. I found the conceptual circuit below online. I understand that Q1 and Q2 are used to provide the necessary supply voltage for the op-...
Navaro's user avatar
  • 922
5 votes
2 answers

Transistors on op-amp power rails

What is the advantage of using transistors on the power rails of an op-amp over more typical boost circuits? I have seen a circuit topology called the "Widlar Boost" made famous by Bob ...
evildemonic's user avatar
  • 9,209
2 votes
3 answers

Current controlled bridge amplifier

This circuit essentially takes a control input and then doubles it when presenting it to the load. I would like a circuit that controls the current to the load. How would I modify the circuit to do ...
Voltage Spike's user avatar
  • 82.8k
0 votes
1 answer

Voltage controlled current source using op-amps

I have a sensor which gives a voltage output between 0V and 5V. I need to transform this sensor output to a current suited for a 4..20mA current loop. The thing is, the current loop doesn't have a ...
Florian Humblot's user avatar
0 votes
1 answer

How can I get/build a current controller/amplifier?

Background: I have a Lorenz-actuator (coil+magnet) that I need to control precisely using a computer. The computer signal is output from a dSpace microLab box as an analog ±10V signal. This signal ...
tomaslimak's user avatar
1 vote
1 answer

Current mirror collector voltage

I'm trying to get the VGS of DMHC4035PMOS. Based on the simulation, I'm supposed to get -5.53V but I'm getting -8.2V on my PCB. Is there anything wrong with the design? What is the collector voltage ...
cy1125's user avatar
  • 201
1 vote
2 answers

Feedback mechanism intuition

There is a circuit taken from the presentation below. Suppose at some point the VFM voltage rises from V0 to V0 + 0.01 V so V_minus of the op-amp rises too. So what causes the voltage on VFM to return ...
lub2354's user avatar
  • 373
0 votes
0 answers

Constant current source with high Vce voltage

At the moment I implemented a current source with two FMMT560 for about 1 mA. These types allow -500V Vce. I expect startup peaks of 520 V which is too much. Are there any current sources which use ...
Gustavo's user avatar
  • 141
0 votes
0 answers

bipolar current mirror, unified control

I'm trying to obtain a high impedance, several decades current pump for charging a capacitor from 1uA to 10mA, swing +/-5V. I arranged two current mirrors like this and is working acceptable for ...
yo3hcv's user avatar
  • 573