Baby Watch Out

It's a very simple circuit, for the follow-up of baby. It can however be also used for other use, as intercom etc. In the place of M1 we can we use a simple electret mic capsule. The regulation of gain becomes from the R1, whoever can be trimmer or potesometer. Has been added also a small automatism, round the RL1 and battery 9V for the case where we have interruption of AC Line. The life of battery is enough big, one and the consumption of current is small, roughly 30 mA, for loudspeaker 8R /0,4W. The transistors do not need heatsink, one and work in Class B.