This timer was found in Japanese documentation from the 1960s. The transistor can be replaced by an equivalent and the relay must be of the sensitive type with voltage according to the power supply.
We found this circuit in a 1967 Experimenters Handbook. The circuit can be implemented with other...
This circuit is from an old documentation but can be implemented with a BD136 for Q1 and 2N3055 for...
In the figure we have the basic configuration of an inverter transconductance amplifier, as...