# is it possible to boost up the current by keeping the voltage constant?

I have a source that can deliver 20mA and 4.5V (MAXIMUM). I need to boost the current to 1 A without using any further source. Also, the voltage should be maintained constant at 4.5V. is that possible with emitter- follower configuration\? if not is there any other solution

• No, the law of conservation of energy applies. You want to take out more energy then you put in. Commented Apr 22, 2019 at 10:09
• Energy is the product of voltage, current, and time. If you need 4.5W constantly, then you can't get the needed power output. If you only need it sometimes, then you could charge a large capacitor from your low power source. Say you need 4.5W for 1 second. That's 4.5J of energy. You could store that amount in a large capacitor. It would take over 50 seconds to store up that amount of energy from your battery. So, high power for one second once a minute.
– JRE
Commented Apr 22, 2019 at 10:17
• You need a constant current of 1A? Commented Apr 22, 2019 at 10:18
• what about if I boost the current and reduce the voltage at stage 1 , then at satage 2 I boost the voltage and then combine the output current of stage one with the output volltage of stage 2? Commented Apr 22, 2019 at 10:22
• If you only need the power intermittently you can look at the chance of adding a storage device like a capacitor, super-capacitor or a battery but this will not magically create more stored energy. Commented Apr 22, 2019 at 10:50

Electrical power, which is the rate at which electrical energy is transferred by an electric circuit is given by $$\P = V*I\$$.