John Robertson wrote:


Google "blue meter" or "Bob Parkers ESR meter".

Indeed, I've been selling those meters since 1999 when I first starting
chatting with Bob Parker (Dick Smith K-7204 kits in those days). Great
ESR meter that works in circuit for roughly values between 4ufd to about
1000ufd.


** I find Bob's ESR meter useful with electro caps anywhere from 1uF to over 15,000uF. It also checks the ESR of tantalum electros. film caps from about 0.47uF upwards - for shorts and opens.

Another use is with batteries, particularly Lithium button cells plus any type of AA, AA and 9V battery.

As with caps, known good examples are your reference and ESR readings rise as the cell goes flat. A 20x3mm Lithium reads about 10 ohms when new rising to 100 ohms or more at end of life.


.... Phil