210 R.C.

Essentially a valve of very high impedance, the 210 R.C. is somewhat restricted in its application. It has, however, a wide application as a replacement in sets designed a year or two ago, where valves of very high impedance were very popular in the detector stage. The high amplification factor makes this valve very suitable for use where the input is rather small. If followed by a transformer, which must have a very high primary impedance, the overall stage gain is high.