I have an amplifier kit, in which it requires a power supply with +24v -24v and ground, the input is and audio jack which is +v and ground , i.e. both of these grounds are connected, i would be using a laptop charger to test the circuit as it needs minimum 19v but the charger has a pin in which i believe there is a + and a ground or - I dont know how to connect the power supply to the circuit as the cirxuit has 3 inputs(+,-,ground) and my power supply has just 2 outputs(+,- or ground) Im pretty new to the +,-,and ground concept and i am confused if i need to connect the - to the ground or not This question is reposted from sound.stackexchange which was off-topic
The word "ground" in an electrical circuit is always a relative term: in fact, it's the "reference" from which every other voltage is measured. *
So, if you have
-24V, that means that if you were to measure the voltage between
+24V you would measure 48V. In fact, if you were to go through all of the documentation and add
24 to all of the voltages, you'd get exactly the same circuit, with
48V everywhere. That would make the novice happier - but confuse the professional no end! A usual audio signal rises and falls above and below some reference point (usually called "Ground"), so you'll get positive and negative voltages.
Your laptop power supply, that has
19V, fits inside the
+24V band. It doesn't work with the
-24V band at all. So you're going to need some kind of adapter or converter to get that to work.
* Note that some circuits distinguish between "analog" ground and "digital" ground. That just means that analog signals reference against one ground, while digital signals reference against a different ground. The two grounds, if you measure the voltage between them, may not have any difference at all - but that's not guaranteed, and connecting the two may introduce interference, especially digital intereference on analog signals.