IDENTIFYING CHOKES..?....

[ve6pg]

..HI FROM TIM...RECENTLY AN ELECTRONICS STORE IN THE TORONTO AREA CLOSED...I PICKED UP A BUNCH OF CHOKES,FER USE IN POWER SUPPLIES..YA KNOW,TYPICAL CHOKE LOOKING LIKE A SMALL TRANSFORMER,2 LEADS,ETC...QUESTION IS,AS THEY ARE NOT MARKED IN ANY WAY,HOW MIGHT I IDENTIFY WHAT VALUE IN MH ARE THESE THINGS?...TNX...SK..

[W1RKW]

I've done something similar.  You can wire the choke in series with a variable resistor.  Put the choke and variable resistor on a signal generator say for around 100Hz.  Measure the voltage across the choke and resistor.  Vary the resistance until  you get equal voltage drops across the choke and variable resistor.  Remove the variable resistor from the circuit being careful not to change its value then measure the resistance with an ohmmeter.  The resistance of the variable resistor (R) will equal the approximate reactance of the choke (XL).  Use XL/2(pi)(F) = L where R=XL to determine approximate inductance.

[KB2WIG]

u can use a GridDipOscilator and STRAP a know value of C accross the L...   tune for dip.....  F and C are now known, solve for L.




u can use vL= L (dI/dT) a couple of ways.............   klc