DIY DB3 Diode Tester 220 ~ 230V

[Kiriakos GR]

DB3 this is special diode which does voltage blocking at anything lower than 30V.
DB3 this is designed to protect Bi-Directional Triode Thyristor Gate input, from false triggering.

In theory, the Thyristor Gate this will be controlled due a B500K potentiometer along with inline power 0N/OFF switch.
DB3 this can be inspected only when there is voltage present,  since the moment that this task cannot be handled due regular DMM and or other measuring instrument, we need one special and safe  DIY electric circuit.

Below is DB3 tester schematic for 220V input.
Along photographs of most popular and SAFE way for the assembly of such a gadget.
This is my own version. 

I think that the use of crocodile clips instead of this connector this is unsafe .

In order to test, remove DB3 from the circuit, insert DB3 at the connector, power on the circuit.
If DB3 this is good, you should expect LED this to start operating by flashing every 2 seconds or less.
When DB3 this is sorted, then there is no need to proceed with this advanced testing. 

[overvolt]

 DB3 Diode Tester this is not a popular topic, but its good to know that there is one !!