1. This type of apparatus has been tried by Mr J. A. Batcliffe for signal-strength measurements, and found to be very useful for this type of work, being superior to an ordinary valve detector on account of its steady zero, and less troublesome than a crystal rectifier.
2. An ionisation or other saturation leak would have to be used to smooth out fluctuations of the bias battery voltage.
3. While in this method, the value of is adjusted to equal the existing value of , the converse method is also possible, and sometimes more convenient. The ratio of is fixed by clamping down the slider B in one position, and the characteristic curves are searched by raising the voltage across AB until a pair of points P and Q are found for which the ratio is equal to the predetermined ratio , indicated by a reversal in the galvanometer deflection.
4. Provided that the valve is operated on a suitable portion of its triode characteristic.
5. As one of the two valves employed is sometimes found to be more sensitive than the other for current amplification, it is advisable to try both in turn and observe which is the better. The small differences in grid current characteristics and hardness, which affect the sensitivity, are not usually apparent in the tests to which valves are subjected by the makers.