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Tools and measuring circuit diagrams
December 29, 2010
The circuit below responds to sound pressure levels from about 60 to 70 dB. The sound is picked up by an 8 ohm speaker, amplified by a transistor stage and one LM324 op-amp section. You... [more]
December 28, 2010
A milliamp meter can be used as a volt meter by adding a series resistance. The resistance needed is the full scale voltage reading divided by the full scale current of the meter movement. So,... [more]
December 25, 2010
The ICL7107 is a 3 1/2 digit LED A/D convertor. It contains an internal voltage reference, high isolation analog switches, sequential control logic, and the display drivers. [more]
December 25, 2010
A simple way to see if a fuse has blown without removing it from its holder. [more]
December 12, 2010
Measures 10mV to 50Volt RMS in eight ranges Simply connect to your Avo-meter set @ 50uA range [more]
December 8, 2010
This circuit uses a CA3420 BiMOS op amp to form a picoammeter with 4 ranges. The exceptionally low input current (typically 0.2pA) makes the CA3420 highly suited for use in a picoammeter circuit. Input transient... [more]
December 2, 2010
This is a simple use of the PIC 16F84 about a diode tester. [more]
November 30, 2010
This circuit is a Logic Probe. It indicates the logic state of the node of any TTL logic circuit. To do that, we have to supply the probe with the same power of the circuit... [more]
November 30, 2010
This circuit runs a fast battery test without the need of power supply or expensive moving-coil voltmeters. It has two ranges: when SW1 is set as shown in the circuit diagram, the device can test... [more]
November 30, 2010
This is a simple servo tester which will comprehensively test the capabilities of almost any modern servo. It has two pushbuttons, CENTRE and SWEEP and a potentiometer which works as follows: - CENTRE Does exactly... [more]
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