Adjustable audible continuity tester
The tester gives an audible indication, making it unnecessary for the user to look directly at the instrument to observe a meter reading. In addition, the curre...
Simple continuity checker
The pitch of the tone is dependent upon the resistance under test. The tester will respond to resistance of hundreds of kilohms, yet it is possible to distingui...
Simple continuity tester
This tester is for tracing wiring on Printed Circuit Boards. Resistors below 50 ohms act as a short circuit; above 100 ohms as an open circuit. The circuit is a...
Simple continuity tester
The pitch of the tone is dependent upon the resistance under test. The tester will respond to resistance of hundreds of kilohms, yet it is possible to distingui...
Simple continuity tester for pcbs
This tester is for tracing wiring on Printed Circuit Boards. Resistors below 50 ohms act as a short circuit; above 100 ohms as an open circuit. The circuit is a...
Single chip checks resistance
A simple tester can be used for routine checks for resistance on production lines of relays, coils, or similar components where frequent changes in resistance t...
Pocket-sized geiger counter
A single 6.75 V mercury battery powers the counter, which features a 1 mA count-rate meter as well as an aural output. A regulated 900 V supply provides stable ...
Clamp-on-current probe compensator
A clamp-on "current probe" such as the Tektronix P6021 is a useful means of displaying current waveforms on an oscilloscope. Unfortunately, the low-frequency re...
Three phase tester
This simple three-phase tester, uses only a small current thyristor as a main element for testing the right or wrong succession of the three phases, and there i...
Phase indicator
The circuit provides a simple means of determining the succession of phases of a 3-phase 120 V source used in synchro work. Terminals A, BT and C are connected ...
Scope calibrator
The calibrator operates on exactly 100 kHz providing a reference for calibrating the variable time base oscillator of general purpose scopes. For example, if th...
dual-trace scope switch
The switcher output goes to the single vertical input of the scope, and a sync line from one of the inputs is taken to the scope's external-sync input. Frequenc...
Ground-earth tester
The circuit is simple and foolproof if wired correctly. Under normal conditions, only lamps 1 and 3 should be lit....
Measuring phase difference
This method is capable of measuring phase between 0 to ±180°. The generated square waves A and are fed to a D flip-flop which gives an output C equal to ...
Diode tester
The circuit will display curves on a scope, contingent on the state of the diode. To ' 'calibrate,'' substitute a 1000-ohm resistor for the diode and adjust the...
Continuity tester for pcb
The continuity tester is for tracing wiring on printed circuit boards. It only consumes any appreciable power when the test leads are shorted, so no On/Off swit...
Power-frequency meter
The meter uses a zener diode to form square waves from input sine waves.
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LF or HF field strength meter
CI and LI resonate on the 1750 meter band, with coverage from 150 kHz to 500 kHz. LI can be slug-tuned for 160-to-190 kHz coverage alone or a 2.5 mH choke can b...
Expanded scale meter
A bar graph driver IC LM314 drives anXED display. The LEDs may be separate or in a combined (integral) bar graph display. Calibration: With a precision meter be...
Phase detector with 10-bit accuracy
Signals of identical frequency are applied to sync input (Pin 6) and to the demodulator input (Pin 4), respectively, the demodulator functions as a phase detect...