All Questions

Filter by
Sorted by
Tagged with
19
votes
3answers
5k views

Difference between 0-18V and -9V - +9V

What is the principle of the difference between a supply which provides 0-18V and +9V and -9V? If I am using a circuit which takes a +/-9V power supply, and instead start powering it with 2 9v ...
6
votes
2answers
3k views

In an ATX power supply, how is the -12V supply made?

I was looking at a pin out for a 20 pin ATX power supply and noticed a -12V pin. I am now wondering; is this just a ground? If not, how does the PSU make a -12V supply rail?
1
vote
0answers
55 views

Apply positive and negative voltage to component using single power supply [duplicate]

I have an electromagnet and a 12V power supply. I would like to apply +12V to the electromagnet at some times and -12V at other times. My current thought is to use four transistors (two NPN, two PNP) ...
0
votes
1answer
67 views

maximum emitter base reverse voltage limiting when driving with op amp?

This is part of a larger circuit, but problem area is shown below. In simulations (of the larger actual circuit not shown), the base voltage of Q1 drops to about -6.35V. Can this damage Q1 (2N3904)? ...
0
votes
1answer
884 views

Switching positive and negative voltage

I struggle to understand how can you switch positive or negative supply from a battery. Firstly, what is a positive voltage and negative voltage? I read many posts stating it all depends on your ...
0
votes
3answers
776 views

Does a high voltage electrostatic precipitator power supply provide a balanced or unbalanced output? [closed]

Does a high voltage electrostatic precipitator power supply create a balanced or unbalanced electrical output in relation to the primary side/ground? If the device provides an unbalanced output, does ...
0
votes
1answer
452 views

Simple Voltage Inverter without using IC

Say I need to create a negative supply rail of -5V (+-0.5V) from a DC input of +5V without the use of any ICs whatsoever. The components available to me are BJTs, Mosfets, diodes, resistors and caps. ...
0
votes
0answers
489 views

Simplest way of getting +/-12V from a 0-12V power supply

This question is probably easy, but as a total electrican noob I couldn't really find a suitable answer so far. Some circuits, like amplifiers, require a -12V and a +12V rail respect to the ground. ...