def _display_capacitance(C):
    """C: capacitance value in F"""
    pF = C * 1000000000000.0
    if pF > 1000000000:
        return '%.2fmF' % (pF / 1000000000)
    elif pF > 1000000:
        return '%.2fuF' % (pF / 1000000)
    elif pF > 1000:
        return '%.2fnF' % (pF / 1000)
    return '%dpF' % int(pF)
