We are offering schering bridgep= r1=consists of ratio dials of 1, 10, 100 and 1000 ohmsr2=consists of ratio dials of 1, 10, 100 and 1000 ohmsc1 = gang capacitor of 500pf.Q = in this arm c1 is placed parallel with r2 to form 2nd arm cdr = c3= consists of three dial condenser box of 0.001x10, 0.01x10 & 0.1x10mfd.R = consists of three dial resistance box of 1x10, 10x10, 100x100 ohms.Unknown capacitor c1 whose value is to calculated is connected in series with r to form 4th arm sterminal for headphone, unknown capacitor & oscillator for provided.