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Repeating Timer No.2

Published:2012/12/5 0:05:00 Author:muriel | Keyword: Repeating Timer

Repeating Timer No.2
This circuit is based on a simple asymmetric oscillator. The length of time the relay remains energized - and the length of time it remains de-energized - are set independently. With the component values shown in the diagram - both periods are adjustable from about 1 to 30 minutes. (View)

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Repeating Interval Timer

Published:2012/12/5 0:04:00 Author:muriel | Keyword: Repeating Interval Timer

Repeating Interval Timer
This circuit has an adjustable output timer that will re-trigger at regular intervals. The output period can be anything from a fraction of a second to half-an-hour or more - and it can be made to recur at regular intervals of anything from seconds to days and beyond. (View)

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24 Second Shot Clock 2

Published:2012/12/5 0:04:00 Author:muriel | Keyword: 24 Second , Shot Clock

24 Second Shot Clock 2
This is a circuit intended to be used in basketball shot clock. (View)

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555 Pulse Generator

Published:2012/12/5 0:03:00 Author:muriel | Keyword: 555 Pulse Generator

555 Pulse Generator
(View)

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24 Hour Timer

Published:2012/12/5 0:02:00 Author:muriel | Keyword: 24 Hour , Timer

24 Hour Timer
(View)

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Asymmetric Timer

Published:2012/12/5 0:01:00 Author:muriel | Keyword: Asymmetric Timer

Asymmetric Timer
(View)

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Periodic Timer

Published:2012/12/5 0:01:00 Author:muriel | Keyword: Periodic Timer

Periodic Timer
(View)

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5 to 30 Minute Timer

Published:2012/12/5 0:01:00 Author:muriel | Keyword: 5 to 30 Minute, Timer

5 to 30 Minute Timer
(View)

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NE555 Monostable

Published:2012/12/5 Author:muriel | Keyword: NE555 Monostable

NE555 Monostable
(View)

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Sound Level Meter

Published:2012/12/4 23:56:00 Author:muriel | Keyword: Sound Level Meter

This is a simple, battery operated, sound level meter using a microphone as input for comparison of sound levels. (View)

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Simple Wideband RF Millivoltmeter

Published:2012/12/4 23:55:00 Author:muriel | Keyword: Simple Wideband , RF Millivoltmeter

Simple Wideband RF Millivoltmeter
Professional test equipment is expensive to buy or hire. But the opportunity is here as below, to emulate a commercial RF millivoltmeter in cheap and simple terms, by its DC output driving a digital multimeter display. In lieu of access to a radio communications test set, frequency bandwidth response can only be estimated as being good to a few hundred Mhz and an input level range from 1mV to a couple of volts rms. Perhaps a reader giving feedback to CXI could firm up these estimates with proper lab kit. So the finished unit will do a satisfactory job for hobby use in fault tracing, gain measurement and general radio test work. Don't forget to halve the indicated DMM reading for the true rms input! Please note this unit is NOT intended to measure RF power, as its sensitive components would be destroyed by the inputting of high RF voltages. (View)

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50hz Calibration aid for Multimeters

Published:2012/12/4 23:54:00 Author:muriel | Keyword: 50hz , Calibration aid, Multimeters

50hz Calibration aid for Multimeters
The purpose of this prototype unit does away with the need for an oscillator. It offers a mains-derived and fully variable 50 hz AC volts down to millivolts for comparison and to check accuracy, of two or more parallel connected multimeters. (View)

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PC Scope Probe

Published:2012/12/4 23:53:00 Author:muriel | Keyword: PC Scope Probe

This simple pc scope probe is nothing more than a fet follower. It has a high input impedance and a low output impedance to match a mic or line input socket on a pc or laptop. (View)

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Small General Purpose Audio Test Set

Published:2012/12/4 23:52:00 Author:muriel | Keyword: Small General Purpose, Audio Test Set

This is a small general purpose audio test set. It comprises a low 0.3% distortion phase shift oscillator and a level meter. The level meter is set at 100mV FSD and can be used for gain measurements and general testing. Current consumption is just under 4mA. (View)

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RF Probe

Published:2012/12/4 23:52:00 Author:muriel | Keyword: RF Probe

This RF probe can be used at High Frequency (HF) or Ultra High Frequency (UHF) on both 50 and 75 ohm coaxial cables. In addition the RF voltage can be measured under load or no-load conditions which allows the circuit to double as an RF Watt meter. The RF probe can be used for oscillators and small transistors for powers up to 2 Watts. (View)

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Transistor Tester

Published:2012/12/4 23:51:00 Author:muriel | Keyword: Transistor Tester

Transistor Tester
A test circuit for BJT (Bipolar Junction Transistors). This circuit can measure both small signal hfe and DC current gain hFE of a low to medium power power transistor. In addition it can measure collector-base and collector-emitter leakage current. This circuit can also measure hFE at different operating points. A multimeter can be used at multiple test sockets to make all measurements, or two DC ammeters can be used. (View)