Schematics of delabs

This circuit uses a LM339, a quad comparator. LM339 can work on single or dual supplies, it has a open collector output that can drive 15mA, low power consumption. The circuit is an untested design but it should work.

Mains Voltage and Power Circuits - Similar circuits for Mains Voltage Monitoring.

There are many better circuits in the various circuit archives i have linked on the front page, you just have to look around. When you measure the open circuit voltage of a battery with a high impedance DMM (10M), the value may be a bit misleading. Apply a dummy load to bleed the battery a bit so that proper readings can be taken on Load. The load below is a 100 ohms wire-wound fusible ceramic resistor which will heat a bit when you test 12V batteries.

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The thermocouples and some other sensors have an output that is non-linear. That means the mV generated by them are not in direct proportion to the parameter measured. In signal conditioning Linearization can be done with cmos fet switches or even comparators and diodes.

In Embedded Systems Linearization is done with Look-Up tables on ROM and also using Math and Formulae for each segment.

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Some outputs are via Dual Differential Line Driver type DS8830. This device will interface with standard TTL systems. The differential outputs are balanced and are designed to drive long lengths of coaxial cable, strip line, or twisted pair transmission lines with characteristic impedances of 50 ohms to 500 ohms. 

Mixed and Interface Circuits

Differential transmission is superior to single wire transmission in that it nullifies the effects of ground shifts and noise signals which appear as common mode voltages on the transmission line.

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The basic digital circuits are Flip Flop and Counter, both are here. This circuit can be cascaded to make even a 6 digit event counter, even a simple frequency counter can be made. 

Digital Timers, Counters and Clocks

These are best done with microcontrollers today. Then what if you have to design your own microcontroller on a FPGA, so the basics have to be sound, hence you have to know what gates, flip flops and counters are.

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This is a modification of a mV Source that can be whipped up easily. You could use a DPM or Multimeter to read the output. The ability of this circuit to perform well depends on the quality of all the MFR resistors and the MultiTurn Pot. Use a Bourns 10T Pot.

Millivolt Source In this link see at bottom this circuit millivolt source

Good Soldered Joints, Keep all Resistors and temperature sensitive parts from Transformer and Regulators. Keep Ripple in power supplies low, no EMI tolerated. If you have problems, make a Battery Powered Unit. Shield well in case you are in a Electrically Noisy environment.

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