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Quick On-Board Junction Tester Circuit Diagram
Short circuits or broken pcb tracks can be easily recognized by means of a Multimeter, but this tool can give wrong results when testing the efficiency of a transistor or diode, unless the device under test is unsoldered and removed from the pcb. A further shortcoming affecting such way of testing is the necessity to keep firmly the probes on the pins of the device under test and at the same time to turn the head continually to read the Multimeter display....
On Off Touch Switch Circuit
The modern mechanic switches are improved concerning of old technology. We need however many times to replacement some old switch or to check currents bigger than the durability of certain switches or simple we need something with modern appearance. For he and different reasons is essential the up circuit. It is simple in the manufacture and the materials that use they exist everywhere....
Infra Red Switch
This is a single channel (on / off) universal switch that may be used with any Infra Red remote control that uses wavelengths between 850-950nm....
This circuit, connected with 32 Ohms impedance mini-earphones, can detect very remote sounds. Useful for theatre, cinema and lecture goers: every word will be clearly heard....
This is a classic divider of frequency via two. It is achieved with a classic circuit T-flipFlop, round IC1 [ 4011 ]. In the circuit, the frequency of network, after are limit the negative half-s period of sine wave and transform in square wave, are divided via two. Thus for frequency50 HZ, we will take in the exit pulse of frequency 25 HZ. The supply of circuit it is + 5V and does not need high benefit in current....
A Simple Shop-Door Alarm
Attach this circuit to the door of an unattended shop - or reception area - and the sound of the buzzer will tell you when you have a customer. Add a siren - and it becomes a simple intruder alarm. Photo...