The Hewlett-Packard Model 5252A Prescaler Unit is a Plug-In unit which converts the Hewlett-Packard Model 5245L Electronic Counter* into a direct reading Counter from DC to 350 Me. Prescaling is accomplished, without tuning, by transistor binary dividers, operating over the frequency range DC to 350 Me. Multiple scaling factors (2, 4, or 8) are provided to shorten scaling time at the lower frequencies. The Model 5252A operates by electronically scaling the input frequency, at the same time extending the counter's time base an equal amount to provide the operator with a direct readout of the input frequency. A LEVEL adjustment permits counting of either positive or negative random pulses. A front panel switch allows selection of a scale factor of 2, 4, or 8 that optimizes the amount the gate time (controlled by the time base) is extended for agivenfrequency input. Multiple scale factors allow measurements at lower freq -uencies to be made without unduly extending the gate time, while providing full capability for direct readout at higher frequencies. For example, the multiplying factor of 8 required when measuring frequencies near 350 Me is not necessary for measurements below 200 Me; hence, multiple scale factors allow the operator to make lower frequency measurements in less time.