Analog Ammeter Protechtion

[hpibmx]

I'm trying to make this diy power supply and I want to protect my analog ammeter from shorts!

I will have digital and analog meter on it, so I will read my short from the digital ( I need to read shorts.)

So I need to have reading on my shorts (on digital) at the same time protect my analog from damaging it, recently damaged 1 of it already.

What I practiced putting a reversed diode but didn't really helped.

any suggestion please?

thank you

[ledtester]

What I practiced putting a reversed diode but didn't really helped.

The way you worded this makes me think you might have put the diode in the wrong way to protect the meter. The diode should not oppose normal current flow.

To avoid having to worry about which way current is flowing through the meter just use two anti-parallel diodes across the meter as shown in this thread:

https://www.eevblog.com/forum/projects/how-to-protect-analog-dc-ammeter/

That thread also has other ideas such as fuses, PTC resistors, buffering op amp.

[BeBuLamar]

Without knowing the burden voltage of your ammeter I wouldn't know if the diode would work. The way to protect the ammeter with the diode is that the burden voltage must be less than the forward bias voltage of the diode. So normally the diode doesn't conduct either way. It will conduct in the forward bias direction when the voltage across the meter is higher than the forward bias voltage.