This amplifier with the EL84 tube is a European commercial type from Corpim mounted on a printed circuit board. The diagram appeared in a September 1958 Radio Electronics magazine.
This circuit incorporates the passive control of the previous circuit and was also found in the...
This configuration is suggested by Mullard (Philips) in an old manual of 555 integrated circuits....
This interesting circuit triggers the alarm when sunlight hits the sensor. The circuit can be used to...