How to Design a Transformer less Power Supply / How Do Chinese Torch Lights Work / How to Charge Ni-Cd Batteries

The below Circuit is same and Suitable for Ni-Cd Battery Chargers, China Torch Battery Chargers, and Transformer less Power Supplies.

The theory is very simple and you simply want to understand Ohms Law,.

Let’s see how we can design and tweak the Circuit as per our requirement.

Design Data required:

1. Input voltage = 230Volts

2.Output voltage = 12Volts

3. Load Current = 32mA

Formula to calculate value of Capacitor and resistor:

For optimum performance and efficiency of the circuit always select R = 100 ohms.

where, units of 

capacitor is in nano farads,

Vin and Vout in Volts,

I(load) = Load Current in Amperes,

R = resistance in ohms,

f = frequency in Hz

By appliying our input and output data in the above formula we get,

C = 477.781nf

Since 470nf is the nearby Standard Capacitor Value we use 470nf for the above circuit.

For Charging Ni-Cd Cells and small Lead Acid batteries in Chinese Torch lights we can use constant voltage charge method and this circuit can be altered to the required voltage and current by using the above formula.

This Circuit is used in Chinese Torch Lights for Charging the battery.

Ask your doubt or clarification in comments.