nº1011

 

Accurate analog computer with 3 bipolar transistors multiplies two DC voltages ranging Vx from 1V up to 5V and Vy from 0.1V up to 0.9V, supply +5V_USB

nº1010

 

Single capacitor symmetrical astable multivibrator, supply +5V_USB

nº1009

 

Minimalist transistor phase-shift oscillator with 7 components. Higher supply voltages allow very low frequency with low capacitor values, supply 24V

nº1008

 

The multimeter dancing needle, supply 3V

nº1007

 

Led chaser with 2 active blue leds changing the stop position, supply +5V_USB

nº1006

 

nº1005

 

Experimental regenerative radio receiver for MW with one transistor; loudspeaker volume, low impedance(32 Ohm) 40mm loudspeaker; random wire antenna with 5mts; mains PE connection; tuning broadcast radio station at 630kHz disted about 30km from 50kW transmitter; groundwave propagation; supply 2xR03. 

nº1004

 

Simple DC considerations about avalanche diode emulator.

nº1003

 

Dual led flasher, supply 230Vac 50Hz

nº1002

 

Mains supplied bicolor led flasher; Flash rate and led color are controlled by a single potmeter.

nº1001

 

Proximity detector with one transistor, supply 2xR03

nº1000

 

Square root(1)

Square root (0,81)

Square root (2)

Voltage square root extractor; about 60mV remaining error; supply +/-5V_USB

nº999

 

Powerbank stand-by mode disabler. Many powerbanks will enter in stand-by mode when load current drops bellow a threshold level ranging from microamps up to about 50mA. Others will start hiccup its output voltage. A simple circuit with 2 transistors will prevent stand-by mode at the expense of only a few microamps.

nº998

 

Simple thermometer with silicon diode sensor can measure outdoor temperatures ranging from -50ºC up to +50ºC, supply 9V

nº997

 

The simplest capacitance meter for electrolytic capacitors with indirect reading, supply 1,5V

nº996

Minimalist led chaser with 2 modes: tact-switch short press runs led ring oscillator; tact-switch long press runs inverted led chaser; supply 3V

 

nº995

 

Reaction time measuring. By pressing COUNTING tact switch a new test is started. The middle tact switch should be pressed as soon as GO red led turns on; waiting time is variable and cannot be predicted; digital voltmeter displays reaction time. (1mS per mV). Pressing RESET tact switch erases current reading for new test; supply +5V_USB

nº994

 

Heads or tails game with 2 mini incandescent lamps, supply +5V_USB

nº993

 

Random flashing led bar; individual stages controlled by SCR, supply 24V

nº992

 

Incandescent lamp flashes controlled by 1 optocoupler, supply +5V_USB