Nicd recharger unit

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I plan on buying some nicd batteries for biasing. However i don't have a charge for them. I only need to charge them initially and not have charge them in the future. Is there a simple circuit i can build to charge them. Avoiding the need for buying a charger for this. How different is the charging of NI-Hydride from NI-cd as i do have a charge for this type of battery. Can i used the NI-H charger for chargin Ni-cd ? or would it blow up in my face.
 
Trickle charge

Yes, you can make a trickle charger out of a power supply and a current limiting resistor.

http://www.greenbatteries.com has some useful FAQs on battery charging. http://www.batteryspace.com has some inexpensive chargers (and batteries).

In general do not switch types of batteries in a "rapid" or "fast" charger unless it has a switch for the two types, or the instructions specifically state that it is a universal charger and senses the battery type. NiCD or NiMH batteries can be trickle charged safely using a power supply and a resistor to adjust the max current to 1/10 the full capacity charge current or less, and charging for nominal time plus 20%, (typically 12 hrs at 1/10 the rate) but you are not guaranteed to get a full charge this way.

Charging any batteries at the wrong setting, or overcharging in general can result in overheating, and leaking electrolyte (white stuff). Most modern rechargeable batteries are vented (those small holes tear the tip), so they will only leak and not explode (bad PR).
 
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