Description

An unusual and useful take on power supplies. It can even keep going if there’s a mains failure.
The idea around this power supply was to build a unit that is fed by a low current source, in the order of 3A, and provide a peak current of about five times higher than this; at 15A. Fifteen amps was sufficient to provide power to all three radios in use, should they all transmit simultaneously. Packet radio usually has a low-duty transmit cycle, where the equipment sits idle, listening for other radio nodes for a very long time, occasionally transmitting.
The additional current supplied to the radios over and above the 3A supply (the primary mains derived source), is taken from a reservoir; a gel-cell battery. Although the power supply was originally designed to run packet radio transceivers, the unit is not just confined to this type of radio. In fact, any radio can be used with this power supply. It can also be used as a main source of power; ie the battery, or used as a standby source of power in the event of a power failure. There would be a float charge for the battery when mains voltage is applied, and the battery can be relied on to supply current to equipment when the mains supply fails.