Sensor-Dimmer (S566B)

In transceivers the desired frequency is often dialled into a frequency synthesiser by means of thumb wheel switches. This type of switch is not particularly cheap, so the alternatiye proposed here is worth considering. This circuit has the added advantage that a new frequency can be selected by means of two push-buttons which can be mounted next to the push- to-talk button on the microphone - a useful feature, particularly for mobile use .