This is the receiver from the previous alarm system. The circuit is from Radio Electronics, April 1989, and has an LDR as the sensor. Optical devices should be used to improve performance.
This phase shift oscillator generates sinusoidal signals in the audio range. Frequency depends on...
We obtained this circuit in an English publication in 1983. Equivalent operational amplifiers can...
The figure shows how to implement an amplifier with gain 10 using the operational amplifier LM41....