Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
Here's the readings on bread-board test, my yellow meter is reading the INPUT mlivokts the ue display is the 4-digit display with the 4th digit covered up. In practice only the first two digits will be read. Note that I used 1K via the 100 ohm preset to calibrate. The final value is equivalent...
UPDATE. Hi Dana, Nigel and all others who contributed logical comments.
The problem unit is assembled on a tiny pcb located a few inches from the display. I decided to build a separate bird's-nest version on the bench, instead of poking in and around the high voltages associated with valves...
Thanks on all contributions so far. I will restate some factors here just to throw a bit more light on it.
1. I am employing a tiny 3-digit 7-sement display unit. I am assured of its linearity and good accuracy on outboard tests. With the unit now removed I am still measuring the under-reading...
Thanks all for your replies and guidance. Analog Kid, the IK5 value was found to bring the gain value to 100 when the 2k preset was centered in its range (this is where 40mV idling current is correctly displayed).
Here are the present inaccuracies:
27mV = 3v6
40mV = 4vO
54mV = 4v4
65mV = 4v7...
I have constructed a metering circuit (pic attached) using one-half of an LM358 as a DC x100 op-amp. The dc output (pin 1) connects directly to a 3-digit voltmeter (1/3rd inch self-type). The source of the voltage to be measured is the cathode of a power-pentode audio-output tube.
The cathode...
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
