Is it possible to make 24 Volts — 19.5?

Good afternoon. Guys, is there a way to make 24 Volt BP - 19.5 Volts PSU?

The network can't find something useful.

Is the laptop, for it needs charging 19.5 There are only 24 Volt power supply (from old printer). To buy there is no desire, as the laptop did not know that. Need a unit to even know included or not included =)

And if the 24 Volt PSU to connect something that will take 4.5 Volts, so will work? =)
July 9th 19 at 10:30
4 answers
July 9th 19 at 10:32
there is a way simple, but "wrong"- take lm'ku to collect linear regulator -excess voltage will go into heat
there is a second way to disassemble the PSU to see the diagram to find the circuit responsible for feedback to modify and replace the resistor/Zener
LM79XX can't do three amps, which eats the laptop. And the power supply from the printer and transformer might be. - orin.Runte commented on July 9th 19 at 10:35
: reinforced lm317 and the transistor will survive - catalina_Sawa commented on July 9th 19 at 10:38
I'm on your shaman do not understand =) I thought that you can just unsolder and solder =) - nickolas93 commented on July 9th 19 at 10:41
: you are absolutely right you just have to unsolder and then solder, but before that we need to think
you feedback can be like a transformer to go to a separate winding, and after the diodes, in the first case it is necessary to think a lot) in the second to find the resistor and Zener diode which are connected to the chip through otprom here it is necessary to change)
there are other less common methods of voltage stabilization in power supply but all at once and not to remember and to describe for a long time) in Chinese PD can for example optocoupler not be quite the word) - catalina_Sawa commented on July 9th 19 at 10:44
: Yeah, you offer a layman in electronics and without the tools to get involved in SMPS? Irresponsible. - orin.Runte commented on July 9th 19 at 10:47
: with this approach you can directly in the store, send, and voltmod BP is no big deal, in any forum for good pictures that prompt desoldering, and what to stick, or at least say that this PSU doesn't ride, "if you do not include the fool", but then apparently the norm to consider any asked a lazy Amateur. - catalina_Sawa commented on July 9th 19 at 10:50
: alas, not all people are interested to stick to the LM317 КТ818 to shake off poor amps. - orin.Runte commented on July 9th 19 at 10:53
: I confess I am also not interested, it is a question of internal struggle toad and hamster. - catalina_Sawa commented on July 9th 19 at 10:56
July 9th 19 at 10:34
You need this device

To him with one hand, you need to connect your PSU, and on the other your laptop. Only here the output voltage will have to configure the voltmeter.
criticizing - offer. Or arguments. - orin.Runte commented on July 9th 19 at 10:37
: This device costs less than a hundred rubles, you need only one copy this time.
Its full twin the fourth year running under load 2.5 A to a remote box on the heating unit in the basement (at an ambient temperature of +60) and no smoke is not allowed, that's two. - catalina_Sawa commented on July 9th 19 at 10:40
July 9th 19 at 10:36
For a start tell full features of the printer power supply (24V you have voiced voicing peak current), then the same for the laptop power supply.
Most likely you will not get the desired power from the printer power supply.
Here's an example before my eyes the power supply from Canon - 24V, 0.7 A.
It is possible to about 0.85 And at 19.5 And this may not be enough for a laptop.
July 9th 19 at 10:38
If the unit is dismantled it is easier to wire 1 resistor(for standard circuit design of switching-mode power supply) to solder a trimpot and adjust to a voltmeter.

Find more questions by tags ElectronicsElements of supply