Free induction transient signals in nuclear magnetic resonance are calculated for solids extending the method of Lowe and Norberg to several pulses. A general formula is given for the nmr signals after 1, 2 and 3 pulses applicable to substances with spins I= 1/2. It contains 9 different types of signals and in very compact form the dependences of the signal amplitudes on experimental parameters — on the phases of the modulation, lengths and distances of the pulses and on the deviation of the exact resonance. Earlier theoretical and experimental results are shown to be included. The most important parts of the formula are checked by experiments. The formula is a good approximation only near the maxima of the signals and must be extended in order to describe the shape of the signals in detail.