Wednesday, December 14, 2011

STABILIZED 2 VOLTS POWER PACK FOR EXPERIMENT 15 & 16


This power pack is designed to replace the lead-acid accumulator in experiments 15 & 16.
Frequently, students tend to make mistakes while wiring up a circuit and cause a short-circuit which would either damage the accumulator or the meters.

A unique feature of this power pack is its built-in electronic short-circuit and overload protection. The l.e.d lights up to indicate normal output but turns off when a short-circuit or overload occurs. It turns off when a short-circuit or overload occurs. It turns on again when the cause of the short-circuit or overload is removed.

Though a common laboratory power supply has a 2 volts output, it is not suitable for these 2 experiments because it consists of pulses of current and is neither regulated nor smoothed. For applications where the D.C. supply has to be steady and unidirectional such as in experiments 15 & 16, a lead-acid accumulator a stabilized power supply with ripple-free outputs has to be used.

Disadvantages of using a lead-acid accumulator in Expt. 15 & 16:
  • It requires regular care and maintenance if it has to last for some time.
  • If it is left discharged to far or left standing for long periods unused the acid attacks the plates to form a heavy deposit of lead sulphate which would be difficult to remove on recharging.
  • If it is charged at too high a rate, considerable heat is generated in the plates which may buckle or crack them.
  • A poorly maintained accumulator would therefore run down rapidly.
Therefore, for reliability and student convenience, our 2 volts Stabilized Power Pack is designed to replace the lead-acid accumulator for these 2 experiments.