Cathode-Coupled Negative-Resistance Circuit

The cathode-coupled negative-resistance circuit is considered at medium, low, and high frequencies. The effects of supply-voltage variations are also treated. It is found that the more common types of dual triodes are capable of developing a negative resistance of the order of 1000 ohms. It is also found that these tubes are useful as oscillators well into the vhf range with this circuit. The assumption is made that amplitudes are sufficiently small to permit the use of linear tube parameters. It should be noted that frequently this is not the case unless some means of amplitude control is provided.