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Latching continuity tester using 4093 - This is a variation on the astable multivibrator. Circuit was recently developed to test for N-MOSFETs (the power kind e.g irf830)
Latching light Detector is frugal with power & parts - 09/26/02 EDN-Design Ideas This idea demonstrates three uses for the humble LED. The circuit in Figure 1a forms a simple light detector that latches and turns on an LED when the ambient light exceeds a preset limit determined by potentiometer P1. LED D1 is both the indicator and the light detector. All junction diodes exhibit some degree of photosensitivity Design by Anthony Smith, Scitech, Biddenham, Bedfordshire, UK
Latching power switch uses Momentary pushbutton - EDN-Design Ideas 01/20/2014 This could be the cheapest way yet to convert a momentary switch into an on-off power controller Design by Anthony Smith
Latching power switch uses Momentary-action pushbutton - 28-Oct-04 EDN-Design Ideas Most inexpensive pushbutton switches, particularly pc-board-mounting and membrane types, have momentary action. Latching types are often larger and relatively expensive, and they frequently are unavailable in the style you'd like to use. You can thus have a problem if you need a small, inexpensive on/off switch for latching power to a load Design by Anthony Smith, Scitech, Biddenham, Bedfordshire, UK
Latching Regulator Prevents Deep Discharge - 03/16/95 EDN-Design Ideas To avoid a deep discharge that can shorten or destroy a rechargeable battery's life, you need to remove the load at the point of complete discharge. Because a battery's terminal voltage recovers after load removal, you can't simply disconnect the load when the voltage dips below a threshold and reconnect it when the voltage returns above that threshold Design by Doug Vargha, Maxim Integrated Products, Sunnyvale, CA
Latching_Relay_Dusk_To_Dawn - Over the years I have had to replace many dusk to dawn switches for outside lights. These switches turn on a light during the night, then switch them off during daylight hours. Some commercial switches are not sensitive enough to detect when the sun is out. Others flutter badly during the dawn and dusk switching transitions, burning out compact fluorescent lamps, which do not like rapid power fluctuations. . . . Hobby Circuit by David Johnson P.E.-July, 2017
Latching Relays - Find out about latching relays and their uses. __ Designed by REUK-Renewable Energy UK website
Low Voltage Latch Circuit - A Discover Circuits visitor wanted a simple on/off latch circuit which can turn on and off power to a small motor. The kicker was that he wanted to power the circuit and the motor from a single 1.2v NiMH
battery cell. Texas Instruments comes to the rescue with their family of low voltage single gate ICs. Specifically the SN74AUP1Q14 Schmitt trigger inverter will operate down to 0.8v and lower. When used with a good NPN transistor, the circuit below works quite nicely. . . Circuit by David A. Johnson P.E.-March, 2013
Low Voltage Latching Relay Driver - Using some small super capacitors, this circuit can latch and unlatch a mechanical relay with 10 amp contacts, from a small 3 volt power source. By using a latching relay, power can be controlled to a load with a tiny battery. . . Circuit by Dave Johnson P.E.-August, 2006
On/Off Latch Circuit - Often you want to turn on and off power to a device with a single pushbutton switch. The circuit below performs this logic function with just a few parts and can operate from DC supplies between +3v to about 15v. It uses two inverters within a 74C14 or a CD4069 hex inverter package. Each press of the button toggles between the two on/off logic states.. . . Circuit by Dave Johnson P.E.-January, 2010
On/Off Latch Circuit with 2 Second Delay - A Discover Circuits visitor needed a latch circuit which could operate using a power supply voltage ranging from 3v to 24v. He wanted to use a tiny pushbutton switch to turn on and off power to a load. However, he wanted a 2 second delay between the switch activation and the state change of the output. . . Circuit by David A. Johnson P.E.-June, 2013
On/Off Switch with Latching Relay - The circuit below switches AC or DC power to a load using an ultra low power 3v latching relay with two coils. The relay can handle about 10 amps of current, up to 250vac. Each time the small pushbutton is pressed, the circuit either latches the relay. . . Circuit by Dave Johnson P.E.-December, 2009
One-button lock provides high security - 03/04/99 EDN-Design Ideas (contains several designs, scroll to find this one) Figure 1 is the block diagram of an easily programmed, single-button combination lock. You operate the lock by using a series of short and long pulses from a momentary switch that masquerades as a doorbell button. The circuit uses inexpensive CMOS
logic. The retriggerable timer, T1, locks out entries made after the T1 code-entry window, thereby greatly enhancing security. The circuit in Figure 2 operates as follows: The Schmitt-trigger quad NAND gate, IC1, debounces the code-entry switch and, with the aid of simple analog circuitry, produces separate outputs for activation times of less than and more than 0.3 sec. These outputs connect to the select gate, IC5 Design by Maxwell Strange, Fulton,MD
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