Assuming the voltage across the transformer secondary be sinusoidal of peak value V_SM, instantaneous value of the voltage applied to the rectifier is given as

V_S = V_SM sin ωt

If the diode is assumed to have a forward resistance of R_F ohms and reverse resistance equal to infinity, then the current flowing through the diode (or load resistance R_L) is given as

i = I_MAX sin ωt for 0 ≤ ωt ≤ π

i = 0 for π ≤ ωt ≤ 2π

Where peak value of current flowing through diode (or load resistance R_L) is given as

I_MAX  = V_SM/(R_F + R_L)

Related Topic 

1. Single-phase half-wave rectifier
2. AVERAGE AND RMS VALUE OF SINGLE-PHASE HALF-WAVE RECTIFIER
3. Efficiency of single-phase half-wave rectifier
4. Frequency Component of Half-Wave Rectifier Voltage and Current
5. Ripple Factor of single phase Half-Wave rectifier
6. Peak Inverse Voltage (PIV) of single phase half wave rectifier
7. Transformer Utilization Factor (TUF) of single phase half wave rectifier 
8. Advantage and Disadvantage of single-phase half-wave rectifier