Sunday, March 29, 2009

Relay Toggle Circuit

Relay Toggle Circuit Using a 555 Timer
This 555 timer circuit below toggles a relay when a button is
pressed. Pins 2 and 6, the threshold and trigger inputs, are
held at 1/2 the supply voltage by the two 10K resistors.
When the output is high, the capacitor charges through the
100K resistor, and discharges when the output is low. When
the button is pressed, the capacitor voltage is applied to pins
2 and 6 which causes the output to change to the opposite
state. When the button is released, the capacitor will charge
or discharge to the new level at the output (pin 3).




Relay Toggle Circuit Using a 556 Timer
This toggle circuit operates by using a couple 555 timers wired
as inverters. Pins 2 and 6 are the threshold and trigger inputs to
the first timer and pin 5 is the output. The output at pin 5 will
always be the inverse of the input at pins 2 and 6. Likewise, the
output at pin 9 of the second timer will always be the inverse
of the input at pins 8 and 12. A 100K resistor connects the
output of one inverter to the input of the other so the state of
one will be the opposite of the other.




Single Transistor Relay Toggle Circuit
The circuit below requires a double pole, double throw relay in
conjunction with a single transistor to allow toggling the relay
with a momentary push button. One set of relay contacts is used
to control the load, while the other is used to provide feedback
to keep the relay activated or deactivated. Several push buttons
can be wired in parallel to allow toggling the relay from different
locations.



CMOS Toggle Flip Flop Using Push Button
The circuit below uses a CMOS dual D flip flop (CD4013) to
toggle a relay or other load with a momentary push button.
Several push buttons can be wired in parallel to control the
relay from multiple locations.




Toggle Switch from A Push On Switch
When there is no toggle switch available, maybe this circuit
can be used for changes. I made this circuit to run a toggle
foot switch, controlling blower table.




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