GeorgeBynum
Active Member
Back in the late 60s and early 70s when I worked (co-op engineering technician) for a two-way radio manufacturer, SMPS were being introduced to us for bench work. THEN, they were a poor choice; a minimum load was required, commonly in the 10% to 20% of full load range. Accidentally operate unloaded and all of the magic smoke escaped. We used HP linears, usually adjustable from 0-32V to about 2A on our development benches. To power the 100W (output) units, most test stations used 40A 5-16V units. We had one test station for stuff that flew and for large trucks, that got to about 36 V ... we had to test to 120% of 28V. 100W and most 25W transmitters still used tube finals with vibrators. We were introducing 25W all solid state units when I graduated in 1972.
