|
 |
DiscoverCircuits.com -- Hobby Corner
Last Updated on:
Tuesday, June 01, 2021 03:06 PM
Hobby Circuits List
The contents &
graphics of Discovercircuits.com are copyright protected.
LINK to Dave's circuit, but DO NOT COPY any files to your WEB
SITE server |
|
|
|
|
More
Driver Circuits, Switches,
Latching Circuits, Relays |
|
ON/OFF SWITCH WITH LATCHING RELAY
(December 24, 2009) |
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 contacts closed or unlatch them open. The 3v powered circuit
uses a single 74HC14. This device contains six Schmitt trigger inverters in the one
14 pin package. Two inverters form a flip/flop circuit. Each time the
pushbutton is pressed, the circuit changes state and stays in that state until the
button is pressed again. With each state change, a 25ms latching or unlatching
pulse is produced and is routed to the correct relay coil. The coil resistance
is about 45 ohms so about 70ma of current is drawn from the 3v battery for each
relay pulse. The average power is so low that the circuit can operate for many
years on one set of batteries. I would suggest using two AA or AAA alkaline
cells. |
|
|
|
|
Click on Circuit Below to view PDF of Schematic |
|
 |
|
|
|
|
|
|
