21-12-2015, 04:43 PM
I wish this guy who wrote the book was a bit more specific in stuff he explains. I've been trying to work out the DIY All-Purpose-Test-Meter schematic. It has about 8 sockets each side for current or for voltage. What throws me is he is he isn't quite specific enough for me to follow which is annoying. Such as, "Run the test lead through the black ebonite socket" and I'm thinking, "What 'test lead?' and what 'black ebonite sockets?' Maybe he refers to the leads from the ammeter but I'd prefer it to be spelled out so I know exactly where I'm at. I've always lacked the ability to summarise and generalise so I tend to need really specific explanations and I dislike it when something is just pulled out of the hat.
At any rate, I'll carry on and fight the good fight. The writer boasts that his meter is a lot more economical than other test meters as it only used 5 Milliamps whereas the commercial ones of the era often used 30 Milliamps. This latter was thought to be expensive in electrics and battery supply. These people had no concept of being able to use digital meter with a small battery.
So far as I can fathom the whole device relies on resistors that are shunted and those in series for voltage. I've never used my calculator so much as recently. That is, I spent some time adding up the meter resistor with the shunt resistor to get the parallel digit value. Sure, I've done this before in text books but not with any actual goal.
You could call this a bit of a rest from the soldering although I still have a tuning mechanism to string and a cabinet to restore.
At any rate, I'll carry on and fight the good fight. The writer boasts that his meter is a lot more economical than other test meters as it only used 5 Milliamps whereas the commercial ones of the era often used 30 Milliamps. This latter was thought to be expensive in electrics and battery supply. These people had no concept of being able to use digital meter with a small battery.
So far as I can fathom the whole device relies on resistors that are shunted and those in series for voltage. I've never used my calculator so much as recently. That is, I spent some time adding up the meter resistor with the shunt resistor to get the parallel digit value. Sure, I've done this before in text books but not with any actual goal.
You could call this a bit of a rest from the soldering although I still have a tuning mechanism to string and a cabinet to restore.
