tag:blogger.com,1999:blog-62404696292674079122024-03-13T12:34:44.219+02:00world technicalWorld Financehttp://www.blogger.com/profile/01757977038242858610noreply@blogger.comBlogger1315tag:blogger.com,1999:blog-6240469629267407912.post-6304073437589646492012-02-22T05:08:00.001+02:002014-11-09T15:48:13.189+02:00missing audio detector
MISSING AUDIO DETECTOR
This circuit detects when audio is not received for about 4 seconds and turns on an alarm.
World Financehttp://www.blogger.com/profile/01757977038242858610noreply@blogger.com0tag:blogger.com,1999:blog-6240469629267407912.post-68615030516764234502012-02-22T05:04:00.002+02:002014-11-05T11:30:04.512+02:00automatic curtain closer
AUTOMATIC CURTAIN CLOSER
This circuit uses a mixture of transistors, an IC and a relay and is used to automatically open and close a pair of curtains. Using switch S3 also allows manual control, allowing curtains to be left only partially open or closed. The circuit controls a motor that is attached to a simple pulley mechanism, to move the curtains.
Automatic Operation
World Financehttp://www.blogger.com/profile/01757977038242858610noreply@blogger.com0tag:blogger.com,1999:blog-6240469629267407912.post-28676214252124980142012-02-22T04:56:00.001+02:002014-11-05T11:04:56.287+02:00tv remote control jammer
TV REMOTE CONTROL JAMMER
This circuit confuses the infra-red receiver in a TV. It produces a constant signal that interferes with the signal from a remote control and prevents the TV detecting a channel-change or any other command. This allows you to watch your own program without anyone changing the channel !! The circuit is adjusted to produce a World Financehttp://www.blogger.com/profile/01757977038242858610noreply@blogger.com0tag:blogger.com,1999:blog-6240469629267407912.post-57619059948110150622012-02-22T04:48:00.001+02:002014-11-09T15:49:05.827+02:00transistor tester circuit
The 555 operates at 2Hz. Output pin 3 drives the circuit with a positive then zero voltage. The other end of the circuit is connected to a voltage divider with the mid-point at approx 4.5v. This allows the red and green LEDs to alternately flash when no transistor is connected to the tester.
If a good transistor is connected, it will produce a short across the LED pair when the voltage is in oneWorld Financehttp://www.blogger.com/profile/01757977038242858610noreply@blogger.com0tag:blogger.com,1999:blog-6240469629267407912.post-3009825743234266222012-02-22T04:21:00.001+02:002012-09-12T17:36:29.693+02:00555 amplifier Circuit
The 555 can be used as an amplifier. It operates very similar to pulse-width modulation. The component values cause the 555 to oscillate at approx 66kHz and the speaker does not respond to this high frequency. Instead it responds to the average CD value of the modulated output and demonstrates the concept of pulse-width modulation. The chip gets very hot and is only for brief World Financehttp://www.blogger.com/profile/01757977038242858610noreply@blogger.com0