Minicounter Support Page

Version 1.0  First Production Release

1. Correction to Manual page 5

The colour code for R8 the 15R LED Backlight resistor should read "Brown, Green, Black". The first 12 kits were issued without an erratum, apologies for any confusion caused.

Version 2.0

1. Frequency Range

The original Minicounter design employed a 74VHCT00N device in the gate circuit. This provided a lower frequency limit below 3kHz. Unfortunately this device is no longer available and so the 74AC00N is supplied instead. This device ensures operation to 135MHz typical, but below 200kHz the frequency count becomes unreliable. This is due to an instability as the LF signal takes the gate bias through it's linear zone. We therefore have amended our specifications to show an operating range of 200kHz to 135MHz. Alternative gate devices and other possible solutions to the instability are being investigated.