Hello. I found a very old telephonic bell, all the internal components were stolen except for the electromagnets. I made it work using a function generator from my school and it works perfect with 20HZ or less AC, with more frecuency it stucks in one position without ringing. I didn't found any information about the kind of circuit that I need, someone has an idea about how to achieve this low frecuency?

 

How much voltage and current does the bell need?
A '555 oscillator will easily do 20Hz at fair voltae and current.

 

Works fine with a wide range of voltage (between 12V and 220V), unfortunately I forgot to measure current. Isn't this oscilator like a clock signal? I mean, it goes from 0 to ΔV, I need something to go from -ΔV to ΔV.

 

The '555 maximum supply voltage is 18V and the output signal will be a couple of volts lower than whatever the supply voltage is. It can provide up to 200mA output current. You can get the -ΔV to ΔV by connecting the signal via a capacitor.

Can you measure the resistance of the bell?

 

If driving an inductive load clamps needed, see various circuits
here where clamps used.

http://www.nutsvolts.com/magazine/article/using-the-555-timer-ic-in-special-or-unusual-circuits


Regards, Dana.