How to increase the current of a DC circuit

Hymie

Joined Mar 30, 2018
970
Besides the mains transformer being uprated for the required current, transistor Q1 will need to be mounted on a heat sink capable of handling the power dissipation*.

Diodes D4, D5 & D6 will need to be uprated to handle the maximum charge current and the value of resistor R5 will need to be reduced such that at the maximum charge current 0.68V appears across it (to switch on transistor Q5).

You will probably need to increase the capacitance values of C1 & C2 by a factor of at least 10.

* with a flat battery and maximum charge current it is unlikely that any size heat sink will be adequate for the power dissipation – so you will need some other arrangement (probably involving an additional 2N3055 transistor to share the power dissipation).
 
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Thread Starter

Marceesty

Joined Jul 27, 2019
4
Besides the mains transformer being uprated for the required current, transistor Q1 will need to be mounted on a heat sink capable of handling the power dissipation*.

Diodes D4, D5 & D6 will need to be uprated to handle the maximum charge current and the value of resistor R5 will need to be reduced such that at the maximum charge current 0.68V appears across it (to switch on transistor Q5).

You will probably need to increase the capacitance values of C1 & C2 by a factor of at least 10.

* with a flat battery and maximum change current it is unlikely that any size heat sink will be adequate for the power dissipation – so you will need some other arrangement (probably involving an additional 2N3055 transistor to share the power dissipation).
This is really helpful, thanks
 

ci139

Joined Jul 11, 2016
1,696
it's where to be cautious ... not a solid rule ... depends on specific transformer (inductance, core) , rectifier diodes (junction capacity reverse leak/-brakedown) and electrolytic capacitors (ESR , thermal characteristics ...) in combination
 
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