Page 2 Electronic Circuits using Zener Diodes

Zener Diodes #'s - N O - Z

Last Updated on: Wednesday, June 02, 2021 05:09 AM

Links to electronic circuits, electronic schematics and designs for engineers, hobbyists, students & inventors:

Original Two-wire Game Show Timer - Several Game Show timers included, scroll to find this one. The game show timer determines which contestant presses their button first by lighting a lamp and ringing a bell and the slower contestants are locked out. The circuit is convenient in that only two wires are needed to interconnect the stations and the wires may all go back to the base unit or they may be "daisy-chained" between stations. There is no electronic limit on the number of stations. The circuit uses a 24 volt power source and 12 volt lamps when built as shown but the experienced experimenter may scale these voltages along with the zener voltages if desired. If the SCR triggers when the power is applied or when the reset button is pressed, add a 0. 1uF capacitor from anode to cathode. (A sudden increase in voltage across some SCRs can trigger them, especially if the gate impedance is high. ) . . . [Charles Wenzel (unless otherwise noted)]

Over Voltage Protection for LM317 - It is a voltage regulator that allows a 6v portable supply to be derived from the 12v car battery. You can add a 6. 2V zener diode and a LED to warn you when the input supply is overvoltage. If you could find a relay that would operate from 6. 2v right up to 12v that you could connect in such a way that if over voltage occurred, . . . [submitted by Adam]

PC Based Thermometer Based on Dallas DS1621 - Since I have no time to build a million pcTHERMs, I give you the plans and the software to build one on your own. This project is easy enough for beginners, the only difficulties possibly arising from serial port hardware incompatibility from PC to PC. In the single-sensor version, you need only the sensor IC, a voltage regulator and and handful of diodes and resistors. Build it, and learn the secrets of IIC bus, how to implement IIC bus using only two resistors and a couple of zeners, how to drive it on a serial port using Visual Basic. . . [Alberto Ricci Bitti]

Power Zener using the LM317 - 10/04/13 EDN Design Idea The LM317 is a versatile regulator. Here, it’s used in shunt mode. . . [by Adolfo Mondragon]

Power-On Time Delay Relay - Here's a power-on time delay relay circuit that takes advantage of the emitter/base breakdown voltage of an ordinary bi-polar transistor. The reverse connected emitter/base junction of a 2N3904 transistor is used as an 8 volt zener diode which creates a higher turn-on voltage for the Darlington connected transistor pair. Most any bi-polar transistor may be used, but the zener voltage will vary from about 6 to 9 volts depending on the particular transistor used. Time delay is roughly 7 seconds using a 47K resistor and 100uF capacitor and can be reduced by reducing the R or C values. Longer. . .

Regulated 12V Supply - This circuit above uses a 13 volt zener diode, D2 which provides the voltage regulation. Aprroximately 0. 7 Volts are dropped across the transistors b-e junction, leaving a higher current 12. 3 Volt output supply. This circuit can supply loads of up to 500 mA. This circuit is also known as an amplified zener circuit. . . [by Mick Devine]

Simple circuit monitors battery voltage - 11/21/96 EDN Design Idea The circuit in Figure 1 monitors four NiCd rechargeable batteries and causes the LED to flash if the voltage of the batteries goes lower than 4V. The circuit consumes only 8 mA of current under normal operating conditions. IC1 is an eight-pin IC that includes an op amp, a comparator, and a 1. 2V zener diode. The zener diode connects to the negative input of the comparator in the IC as a reference. R6 and R7 divide the battery voltage. . . [by Yongping Xia, Philips Lighting Electronics Co, Torrance, CA]

Thermometer Based on Dallas DS1621 - Since I have no time to build a million pcTHERMs, I give you the plans and the software to build one on your own. This project is easy enough for beginners, the only difficulties possibly arising from serial port hardware incompatibility from PC to PC. In the single-sensor version, you need only the sensor IC, a voltage regulator and and handful of diodes and resistors. Build it, and learn the secrets of IIC bus, how to implement IIC bus using only two resistors and a couple of zeners, how to drive it on a serial port using Visual Basic. . . [Alberto Ricci Bitti]

Two-Watt Switching Power Supply - In this small switching power supply, a Schmitt trigger oscillator is used to drive a switching transistor that supplies current to a small inductor. Energy is stored in the inductor while the transistor is on, and released into the load circuit when the transistor switches off. The output voltage is dependent on the load resistance and is limited by a zener diode that stops the oscillator when the voltage reaches about 14 volts. Higher or lower voltages can be obtained by adjusting the voltage divider that feeds the zener diode. The efficiency is about 80% using a high Q inductor. . . [Bill Bowden's website]

Zener Diode Tester - This zener diode tester can be used to check zener diodes of 3. 3V to 18V. The breakdown voltage of the unknown zener diode is indicated on the precalibrated dial of potmeter VR1. The tester can also identify the polarity of zener diodes. . . . [© EFY Enterprises Pvt. Ltd. All rights reserved.]

Zener level-shifter drives high-side switch - 06/16/2014 EDN Design Idea implify a high-side driver by replacing a transistor with a Zener diode. Microcontrollers, the heart of all modern electronic gadgets, are increasingly powered with sub-5V power supplies. This complicates the control of external loads powered by higher voltages. . . . [by Dhananjay Gadre & Nidhi Sharma]

Zener regulator - A 13 volt Zener diode will work well for charging a 12 volt battery on Standby use. Or use a 14 volt zener a diode for a Standard 14. 6 volt charge. . . . [G.L. Chemelec]

Zener Value Evaluator - Using this simple circuit and a known-value zener diode, you can find the breakdown voltage value of any zener diode. The circuit is divided into two sections: zener evaluator and display unit. Regulated 12V and 5V are required to power the zener evaluator section, while the display section works off only 5V. Connect +5V, point A and ground of the zener evaluator section to the respective terminals of the display section. . . . [© EFY Enterprises Pvt. Ltd. All rights reserved.]

Circuits using Zener Diodes #'s - N O - Z