magnetic switch activated alarm
Posted: Sun Jun 05, 2011 3:10 pm
Hello,
I assembled a circuit on a breadboard which is separated in 2 parts:
the right part is for generating an alarm which wails.
the left part is for starting the current flow to the first part when the magnet is detached from the reed switch.
Apparently the 1st part works (I get the wailing sound).
The second part almost works (the relay switches when I remove the magnet).
But no current passes through the negative part of the relay to the 1st part.
(I checked with the meter).
I attach a photo of the breadboard and the schematic, the components are :
three n2222 transistors
two n6027 programmable unijunction transistor
one 4001 diode
a dpdt 12v relay
a reed switch and a small magnet
(plus various capacitors and resistors)
The current is 12v dc
I assembled a circuit on a breadboard which is separated in 2 parts:
the right part is for generating an alarm which wails.
the left part is for starting the current flow to the first part when the magnet is detached from the reed switch.
Apparently the 1st part works (I get the wailing sound).
The second part almost works (the relay switches when I remove the magnet).
But no current passes through the negative part of the relay to the 1st part.
(I checked with the meter).
I attach a photo of the breadboard and the schematic, the components are :
three n2222 transistors
two n6027 programmable unijunction transistor
one 4001 diode
a dpdt 12v relay
a reed switch and a small magnet
(plus various capacitors and resistors)
The current is 12v dc
- alarm-reedSw-breadB.jpg (120.54 KiB) Viewed 5193 times
- schematic-relay-reedSw.gif (9.46 KiB) Viewed 5193 times
- relay-reedSw.gif (17.48 KiB) Viewed 5193 times