The applications of this circuit are FM tuning indicator, Stereo Balance Indicator, Wire T2 like T1 then we get two channel inputs and battery level indicator.
This circuit is derived from a Siemens Application Note 1974.
This circuit uses common components of today. The circuit is
here as it is of high educational value.
You can 'simulate and test' or 'wire it up and try' and let me know how it worked. The Circuit is also a simple analog to digital converter. You can use optos in place of LEDs.
Monitor for your Boat or Car
T1 and T2 make a differential amplifier. T3, T4 and T5 driving the LEDs are comparators.
When input voltage is increased T1 is turned on which leads to more base current for T3 which Lights LED1. When input voltage is less T2 turns on as it gets a better base current from P3 which turns on LED2 via T4. When both LEDs are off T5 gets biased as no drop across R5 which lights the LED3 thru T5 hopefully.
Back to Circuits using discrete
20th May 2020
The documents, software, tools and links are provided to enhance the ability of an electronics student, hobbyist or professional by sharing information. The information, links etc. should be used by the website visitor, at his or her own risk and responsibility. There may be concept, design and link errors in the pages.
Creative Work, ideas and documents of delabs can be used for Product Design and Development by R&D Engineers, Hobbyists, Students and even firms for creating useful products. These cannot be used for reprint, replication or publishing online or offline.