I've never seen a commercial radio that had a diode in series with the 12v input. Instead they put a diode across the power input so that it conducts if the input power is reversed and blows a fuse.
I like?Phil Salas AD5X idea for an over voltage AND reverse voltage protector.
Max KG4PID
On Sunday, September 4, 2022, 11:26:25 PM CDT, Ashhar Farhan <farhanbox@...> wrote:
The polarity protector is the better idea. Simply because the diode can get very very hot. The sbitx can draw upto 10A of current. Across a diode like 1N4007, the voltage drop is about 0.7V, the diode will have to dissipate 10 x 0.7A = 7 watts of power during transmit. This is one reason why we don't switch the power to the power amplifier through T/R line, the power involved is just too much.
On Mon, Sep 5, 2022 at 9:29 AM otalado <s53c.lado@...> wrote:
Hi, Gordon while it is true that just showing a diode into the power supply line is cheap & quick, the solution you suggested is, without doubt, a lot better. In fact, I'll order (or produce) some PCB for the protector. Yet I strongly believe that such protection should always be built inside the box that needs protection!
