Here is the Current booster circuit using transistors. Normally 78xx regulator series ICs can power max output currents of 1 A. Or in the common usage, it is only up to 0.6A. But we need more current up. You must buy a new one, like a 78H05 voltage regulator, LM350, or LM338, etc.
But it is expensive. How do you do? Read this may be alternative good for you. Don’t worry you can use the current booster circuit for 7805 (78xx).
Current booster circuit for 7805
In this increasing Regulator Current or circuit, the power transistor is used to provide most current to the load, to maintain a constant voltage, by the little current still through the regulator IC intact.
Let’s say, I want a 12V voltage regulator, and the current output voltage at 5A, I must to use an IC No. 7812 and it can take a transistor number MJ2955 or TIP2955. The input voltage is enough I think that about 20V, which voltage drop across the transistor is approximately 8V. And it takes about 40Watt energy, which can be calculated = Vce x Ic. When is this. We need a cooling pad for Q1, which is large enough, it is very hot, maybe cause damage.
If you want to add current to the IC 79xx or negative voltage, you can also easy to make, but simple NPN transistor type 2N3055 is only a number.
10A fixed regulated Supply using 78XX – MJ15004
If you have a lot of old pieces of equipment. You may build a 10A DC power supply circuit.
That be simple please, when I sees the equipment that him has had already. Then take this circuit see use 78XX integrated circuits. Have many the number and Transistor power number M15004 that can enhance current. Get tall arrive at 10A.
The important aspect is must use the Transformer that be appropriate give current 10A More than. And use C-Filter 10000uF sizes go up with. The detail is other see in the circuit has leisurely sir.
Increase current of 7805
But above circuit not have protection over load
We need to use the below circuit!!
Sometimes we want to use. high current at a dc regulator 5v 3a. We can do this by using the voltage regulator IC1 positive constant number 7805.
The Q1-2N3792 and Q2-2N5956 of the circuit will serve to increase current for the IC regulator.
The R2 acts as the anti-saturation of Q12N3792 and Q2-2N5956. Without R2 will allow the two transistors to do not work. The output current can be from IC1 alone.R1 specify the bias current to IC1. And the current output of you against too much saturated with.
The C1 functions in the input power filter to smooth. And C2 serves to prevent interference with the pressure to payout (Vout).
This circuit can help enlarge the current of the power supply circuit that uses an Ic regulator so well. you can use other IC 7805,7809, IC-7812, and IC7815.
Q1 is BFX88 or Equivalent
Q2 is BD132 or Equivalent
Learn how to increase the current of 7805 with 2N3055 transistors
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This circuit requires enough power supply. Do you have this one? If you do not have it. Look:Learn Many Power supply circuits
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15 thoughts on “Current booster circuits for IC-78xx”
Hi, I am confused with the output voltage marking on the circuit diagram, it says +15V, whereas the topic / issue is only 5 volts.
Is this a typo-error? please do correct, as I like this simple to do/construct project for high current 5 volts circuit.
Can you tell me the other equivalent of 2N3792 transistor?
More power to your site.
Thanks in advance.
hi,i am confused with working of current boosting circuit and calculation that are used in dual polarity 15V power supply. what is requirement of over voltage protection circuit?
if its 7805 will be stabilized to 5v if you put 7815 it will be 15v. the transistors allow a higher current, than the IC delivers by its own.
How this circuit is working with a pnp transistor ? I know a circuit with npn transistor 2n3055 with base connected to regulator out and collector to input power and final out taken from emitter and ground. But how a pnp transistor circuit is working ? Please explain?
It is very interesting. We are doing this. Please wait for about 1 week. a new update to explain its works on 2N3055.
I have also same question… did you find any answar..?
Please learn more: https://www.eleccircuit.com/experiment-increase-current-7805-2n3055-transistors/
Hello all…. Finally got the steps to increase the dc current in this page after a long search in internet…
But i have to know some more suggestions before i do any damage to my device….
Let comes to the point. I have a poly crystalline solar panel rated 5 watt, 18 volt max, 0.2A. I’m tried to build a solar phone charger and got partial result…. I.e my phone is charging at very slow rate….one percent charge takes nearly 40 mins….
So i need to increase the current to 1A from solar panel…… Will using the above circuit damage my phone or shall i move on to build.
If anybody design circuit for my solar mobile charger that would be thanks….
I am looking for a schematic for a good oscilloscope if you have any please can sen me
What are the voltages values of C1 and C2? It is rated 470uF, at what voltage?
Do you have a design for a 0-60VDC, 100A adjustable output, regulated power supply?
Can the necessary current like 10A can be achieved by transistors 2N3792 and 2N5956 alone without regulator IC 78xx? What is the purpose of the regulator IC 78xx.
We need to use a 78xx regulator. Because it helps to set the constant voltage at the output.
C1 needs to be removed from this and all other copies of this schematic across the internet. Have you even tried out this circuit? Because of C1 (I know because I’ve tried) your output voltage will spike to Vin until C1 charges. Just remove it. There should be no capacitors between the resistor feeding the 78XX and ground. Put them before, put them after, but NOT IN BETWEEN.
Hello Robert Stoddard,
Thanks for your visit. And thank you very much For your useful comments.
Yes, I have never remove it. My teacher put it. I make like him.
It is good you tried it with yourself.
If I have free time I will try it too.
In my city, I had just had a great flood. My laboratory was damaged.
So I thought of building a new house. And all new laboratories.
I hope you will return to give good opinions. Like this again.
Thank you very much, can we be friends?