These are Instruments that Jack built.
Here read Jack as me, delabs. Some
were hand made, some in the form of
workflow of a small firm with
professional equipment. Some
made in quantities, other a couple or
more for R&D.
Test and Measurement is all about
Measurement or Metrics. Without this,
every other part of electronics
becomes like boneless entities.
Reverse Bias Leakage Tester
Instrumentation and Automation
In Test and Measurement and
Industrial Process Control a common
factor is instrumentation. The
measuring aspect is common to both.
T&M instruments are used in
Testing, Research,Automated Testing,
Troubleshooting and Servicing.
An early T&M company was the
and Goltermann - Communication
Process control Instruments are
used in Production Lines made of
Machines in a Factory. It could be
Counters and Timers used for Textile
or Steel Industry. It can also be
Temperature and Pressure Controllers
used in Oil Refining or Food
So you see a difference. We have
handheld Test Instruments like DMM
and Scope and We have Handheld
Instruments for Gas Monitoring or
Humidity too. In automated testings
we have rack mount test instruments.
In Control panels we have Rail Mount
carrying DIN standard Instruments.
to Build Lux Meter - ELM
Points in Instrumentation
- On-Off controls or level trip
relays can oscillate if hysteresis
dead band is very small or absent.
- Hysteresis is like on at 300 off
at 304 like in heaters or air
conditioners. If you on-off at
sharp 300 there is a chatter or
oscillation. This is called
dead-band in temperature control.
In above example 304-300=4 is the
- LF356, TLO71 and CA3140 are FET
input Op-Amps, the bias is in pA,
The caps for sample hold with
these opamps are low leakage
ones.10uF tantalum for long time,
low resolution data. Long hold
times with 12 bit data (analog)
use 1uF plastic multilayer and
clean-IPA + coat PCB with epoxy.
- Design the product in such a way
that neither the pot terminals or
pot switch is used for mains
voltage, instead use the pot
switch or variable resistance for
signaling and the mains can be
switched with Relay or Thyristor.
- If you need a 10.00K resistor
0.1% and you only have 1% in the
market, you can trim lower values
to higher values by removing the
paint of the resistor and
scratching the black metal film
till you get the desired value.
(this is only for testing or
prototype development, R&D,
not for manufacturing).
- 7107 and 7135 of Intersil can be
tested in-circuit, check Vref for
100mV or 1V reference, then short
Vin and Vref the reading should be
1000 counts for 7107 and 10000
counts for 7135. ground plane
should be good, no ground loops,
PCB only glass epoxy and low
leakage caps to be used, then
reading will be stable, use some
coating on soldered PCB.
- An electrically Noisy
environment can be simulated with
a hair drier, or hot air blower.
Another way Looping the NC
(normally closed) contacts of a
230V Electrical Contacter-Relay
can make it oscillate, this makes
a lot of Sound and more important
is the Electrical noise rich in
EMI-RFI. This helps basic testing
of timers, counters, uP, uC and
embedded systems as they may
malfunction in noisy environment.
- A Single Pole 12V 100mA relay in
a feedback loop, with its
contacts, can make a Electrical or
Electromechanical Oscillator. This
can test your ground loops and
digital circuit decoupling caps.
It simulates power spikes which
may reset some counters.
- When a Machine with many stages
or even an entire production line
has to be automated, a PLC system
is easiest to configure. It has
digital inputs for limit switches
and proximity sensors, it has
analog inputs for any other
parameter sensor. The PLC output
modules can drive Electrical
Contactor circuits with 230V
Signal or 4-20 mA for an AC drive.
The tacho-generator voltage
feedback or pulses feedback from a
motor can be fed to PLC inputs
- Automation is used to enhance
the quality and quantity of the
product, also where there is
danger to operators or workers.
This moves the worker up, into the
maintenance and management of
materials, machines and systems.
- Industrial Automation is
essential to enhance the
manufacturing worker to deliver
consistent, repeatable and timely
delivery of products. Absence of
automation makes quality and
deliveries unpredictable and
stresses worker on monotonous
jobs. When the worker is
creatively employed with his
machine on automation, it is the