The transformer core steel most often used in vibrator transformers are limited to four grades. These grades are usually designated by their specified core-loss characteristics as expressed in watts-per-pound, at a flux-density of 10,000 Gauss and 60 cycles-per-second frequency.

In order to stabilize the circuit and suppress this spurious oscillation, a resistor is placed in series with the secondary timing capacitor. The value of this resistor must be such that the critical damping resistance of the unwanted LC circuit is exceeded, while the critical damping resistance of the desired LC circuit is not reached.

The vibrator starting characteristics are quite important to the transformer but are often neglected. A serious transient condition may be imposed on the transformer by the vibrator during the first few cycles until the full operating frequency of the vibrator is attained.

The transformer used in a vibrator power supply is a very important and critical component. As one of the three principal components (the other two being the vibrator and the timing capacitor), its design and performance can control the resultant vibrator performance.

The selection of the most suitable vibrator can be made with relative ease. Most of the factors which govern this choice are controllable or are known at the beginning of the design work.

Time intervals "ti" and "t3," as before, represent the contact-closure time for the interrupter portion of the vibrator.

All of the previous discussion has been with regard to "Standard Frequency" vibrators, whose nominal frequencies are 115 cycles per second.

Many direct and indirect factors have an important bearing on the overall design of the power supply system and to the selection of the most suitable type of vibrator in particular.

From the above calculations and characteristics, it will be noted that the estimated input current at 2.0 volts CT, is well within the maximum value allowable for reasonable life expectancy.

The shunt-coil system employs a simplified mechanism as compared to the separate-driver system, for it requires fewer parts and adjustments.